DESC:TECHNICAL FIELD
The present disclosure generally relates to the field of a Material sciences and Electrochemistry. In particular, the disclosure relates to electrical energy storage devices containing lead-based perovskite anodes. The present disclosure also provides Lead-based Perovskite-type Anodes for Safe High Energy Density Non-Aqueous Secondary Batteries.

BACKGROUND OF THE DISCLOSURE
Perovskites are a crystallographic family with simple ABX3 stoichiometry with remarkable electronic and photonic properties. Perovskites (originally CaTiO3) hosts A ions at corners, B ions at body center, and O ions in X positions at face center. They are used in dielectric, ferroelectric, piezoelectric and solar energy generation applications. Hybrid perovskites have typical A(BB?)X3 stoichiometry. Perovskites and hybrid perovskites have emerged as potential materials with their unique applications in photovoltaics, optoelectronics, lasers, and electrochromism. Many derivatives of the perovskite structure exist, where A and B cations are replaced by large molecules, so long as the Goldschmidt’s tolerance factor is satisfied. This factor also determines whether the end structure is orthorhombic, cubic, or tetragonal. Lead halide perovskite is one such complex perovskite derivative that is popularly explored in solar cells. Perovskites having empty d states in cation B (like PbTiO3) are band insulators, while those like ReO3 are conducting due to sigma overlap of valence orbitals lobes of oxygen and Rhenium.

Structurally, signs of ion transport in form of linear channels made of A cation chains (here Pb), forming a 3D network, are present in all three directions, parallel to 3D corner shared BO6 octahedra chains. However, along these channels, the bottleneck, a 4 Oxygen coordinated region (O4 window) is too small to allow A ion flow. In another case, the A ion free perovskite-like structures such as ReO3 has void O4 bottleneck space smaller than mobile ion. Octahedra, owing to corner sharing, rotate to lock incoming ion somewhat permitting ion mobility. LixReO3 structure is one case that allows restricted ion mobility. This concept was extended by Cava, Murphy et al, for related structures like FeV3O8 which have a perovskite like 12 oxygen coordinated voids that occur in many other structures. Further, in such A ion free ABO3 case, a very large space is present for lithium ions to move around. The number of such free available sites is critical to fast ion transport as seen in a-AgI that displays an unusual BCC structure. Here Ag is in a quasi-liquid state and hops interstitially. Additional factors promoting fast Ag motion are its low coordination number and low polarizability. Nb2O5, its polymorphs and related Ti and W substituted phases, make up perovskite like structures, where rotation is stopped and tunnels are wide open for lithium ions to flow freely. This is possible as the perovskite type structure here slightly becomes more rigid in two ways. First, by addition of some edge sharing where the entire perovskite structure is sheared into blocks. This gives rise to family of Wadsley-Roth phases. Here lithium is only allowed to flow down the tunnels of a block, while it is not between blocks. Second, by introducing some octahedral rotation instead of shearing, Bronze phases develop. Very interestingly, in Perovskites, fast ion transport is possible for the anionic X position as depicted by F- super anionic conductivity in NaMgF3. This is like the fluorite CaF2 structure where the F- anions are mobile - one very popular example being yttria stabilized ZrO2 (YSZ), used as solid electrolytes in fuel cells, where oxygen defects promote to its mobility. Ca2+ cations, even at 50% filled, form the rigid sublattice and are not mobile due to large energy needed in the normal tetrahedral – interstitial octahedral site hop. Fast cation transport occurs in M rich anti-perovskites (M3AB), where the cation (noted as X) and anions (noted as A and B) are interchanged. X positions (in X3AB) are occupied by excess M alkali ions. Due to high cation conductivity, they are used as M alkali ion conducting solid-state electrolytes. By switching some M cations with a transition metal redox center, the new anti-perovskite structure can be used as an insertion battery material. However, in perovskite ABX3, due to geometrically lacking cation mobility, to use it for energy storage in rechargeable alkali ion batteries, they must contain elements capable of undergoing alloying and/or conversion reactions. Barely 3 years following 1991’s SONY’s introduction of Li-Ion battery, Fuji Photo Film Co. in a 1994 patent showed that a Sn-based amorphous tin composite oxide (ATCO) glass gave 4 times volumetric and 2 times gravimetric anode energy density than graphite. On the basis of this idea, a new company Fujifilm Celltec Co., Ltd. was established to develop and produce a new generation of lithium batteries such as the STALION Cells (meaning Sn based Li-Ion) and related products. Enlightened by this, there was an instant swing in research activity over the next decade to study Sn alloying reaction in an array of starting materials with Sn alloying center. Apart from Sn based borate/phosphate or silicate glasses, spinels, hollandites, many ASnX3 type phases with different A elements were tested in the 2000s and shown to store lithium reversibly by conversion-alloying reaction. CaSnO3 was first studied by Chowdari et al. Others similar compounds include CdSnO3, NiSnO3, ZnSnO3, CoSnO3 and BaSnO3. Some studies were done on Ti-based perovskites. While, Li0.5La0.5TiO3 is an insertion anode operating on the Ti redox and storing around 225 mAh/g without structure breakdown, Na0.5Bi0.5TiO3, like the Sn compounds, uses Bi alloying center to store Na ions by conversion-alloying process. Organic-inorganic lead halide perovskite also store lithium ions by a similar framework breakdown-Pb alloying mechanism, but are not promising due to their poor pristine structure stability. In this aspect, experimental proof using PbTiO3, PbZrO3 is pursued and presented here for the first time as potential ABX3 candidate for battery anode materials.

Tin was widely used as Li-alloying center of choice in amorphous glass, perovskite, and numerous other structures as lithium-ion battery anode following Fujifilm Celltec Co. Ltd.’s 1994 seminal patent on use of tin-based ATCO glass in camera batteries as LIB anode with higher energy density than graphite. It has been recently reported that Na0.5Bi0.5TiO3 perovskite with Bismuth was employed as as Na-alloying source in sodium-ion batteries. Studies were carried on a titanate perovskite Li0.5La0.5TiO3 which was used as an insertion anode for lithium ion batteries delivering 225 mAh/g. Although, several perovskites are reported in the prior art for their storage applications, they were reported to have drawbacks. For instance, organic-inorganic lead halide perovskite store lithium ions suitably but these are not promising due to their poor pristine structure stability. Therefore, there is an unmet need to develop a potential ABX3 candidate for battery anode materials. The invention aims to prepare compounds with elementary ABX3 perovskite structure for use as electrode materials in high energy density rechargeable batteries. Perovskites (originally CaTiO3) hosts A ions at corners, B ions at body center, and O ions in X positions at face center. They are used in dielectric, ferroelectric, piezoelectric and solar energy generation applications.

STATEMENT OF THE DISCLOSURE
With respect to the mentioned prior art, it is an objective of the present invention to provide an advantageous electrical energy storage device with safe and energy dense anodes for alkali-ion rechargeable batteries with extreme ambient stability.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

This objective is solved by an electrical energy storage device comprising a lead-based perovskite anode.

The present invention relates to an electrical energy storage device comprising a lead-based perovskite anode.

The present invention provides a lead-based perovskite with PbXO3, wherein X is selected from a group comprising titanium, zirconium, silicon, iron, niobium, nickel, zinc and combinations thereof.

The present disclosure provides non-aqueous M-ion rechargeable batteries (M = Li, Na, K) comprising lead-based perovskite anode, a cathode and an electrolyte.

It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
FIG. 1 shows rietveld refinement of XRD (Cu Ka) pattern of (Left) PbTiO3 synthesized by solution combustion and (Right) PbZrO3 synthesized by solid-state synthesis. Experimental data points (grey filled circles), calculated pattern (red line), their difference (blue line), and Bragg reflections (black sticks) of the tetragonal P4mm phases are shown. Inset shows the representative crystal structure (Pb = black balls, TiO6 = distorted blue octahedra).

FIG. 2 shows electrochemical performance of combustion synthesized PbTiO3 vs lithium. (a) Voltage vs Sp. Capacity plot, (b) Capacity fade, (c) Differential capacity curve (dQ/mdV) for the first two cycles, (d) TEM SAED patterns of the (e) PbTiO3 and (f) Pb particles obtained from exsitu samples cycled to 0.5 V vs Li+/Li.

FIG. 3 shows electrochemical performance of combustion synthesized PbTiO3 in sodium-ion and potassium-ion batteries. (a,b) Voltage vs Capacity curves, (c,d) Differential capacity plots for the first two cycles.

FIG. 4 shows voltage profile of electrochemical performance of PbTiO3 and PbZrO3: (a) Voltage profile, and (c) Differential capacity plot versus lithium. Electrochemical performance: (b) Voltage profile, and (d) differential capacity plot of first two cycles versus sodium.

SUMMARY
Pb-based perovskites, PbTiO3 and PbZrO3, synthesised by solid-state (dry) and solution combustion (wet) routes, have been introduced as anodes for a variety of alkali-ion (M = Li, Na, and K) batteries. First, the parent perovskite materials irreversibly convert to Pb, M2O and other oxides at a voltage depending on the stability of the parent material. Next, in the inactive oxide matrix, Pb undergoes reversible (de)alloying reaction with M, forming at least two intermediate line compounds (or alloys) as per Pb - M phase diagrams. The end phases formed at the end of the first discharge are most likely Li4Pb (568 mAh/g), Na3.75Pb (485 mAh/g) and K1Pb (130 mAh/g) based on the number of M inserted, 1 per mole of starting material. Irreversible (discharge) capacities for PbTiO3 were 700 mAh/g for Li/Na and 450 mAh/g for K. The reversible (1st charge) capacities for Li/Na were 410 mAh/g and 180 mAh/g for K. While the alloying reactions occur below 1 V, charge storage in initial cycles near 1.5 V, particularly for Na/K, is either from TiO2 insertion, or PbO conversion reactions. This mechanism will happen in related Pb(B?B??)O3 mixed perovskites, and other unrelated structures containing Pb. Much more higher capacities are likely in cases where multiple cations can form an alloy with M. The mechanism is independent of synthetic route and material, as similar charge storage behavior was observed in PbTiO3 and PbZrO3 made from both solid-state and solution combustion routes. Pb-based perovskites offer a safe repository of Pb and other alloying elements for use as anodes in high energy density batteries. Commercial use and later recycling of Pb-based perovskites is likely to benefit from the routine handling of Pb in lead-acid batteries.

DETAILED DESCRIPTION OF THE DISCLOSURE
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the description of the disclosure. It should also be realized by those skilled in the art that such equivalent methods do not depart from the scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” or “containing” or “has” or “having”, or “including but not limited to” wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a method that includes a list of acts does not include only those acts but may include other acts not expressly listed or inherent to such method. In other words, one or more acts in a method proceeded by “comprises… a” does not, without more constraints, preclude the existence of other acts or additional acts in the method.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification may not necessarily all refer to the same embodiment. It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Equivalents:

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

The present invention relates to an electrical energy storage device comprising a lead-based perovskite anode.

The present invention relates to an electrical energy storage device comprising a lead-based perovskite anode, a cathode and an electrolyte.

In a non-limiting embodiment of the present disclosure, the electrical energy storage device is selected from a group comprising a rechargeable battery.

In a non-limiting embodiment of the present disclosure, the rechargeable battery is selected from a group comprising Li-ion battery, Na-ion battery and K-ion battery.

In a non-limiting embodiment of the present disclosure, the electrical energy storage device is a rechargeable battery.

The present invention relates to rechargeable batteries device comprising a lead-based perovskite anode.

The present invention relates to rechargeable batteries comprising a lead-based perovskite anode, a cathode and an electrolyte.

The present disclosure provides non-aqueous M-ion rechargeable batteries (M = Li, Na, K) comprising lead-based perovskite anode, a cathode and an electrolyte.

The present invention provides a lead-based perovskite with PbXO3, wherein X is selected from a group comprising titanium, zirconium, silicon, iron, niobium, nickel or zinc, tantalum, germanium, or tin and combinations thereof.

In a non-limiting embodiment of the present disclosure, the lead-based perovskite is selected from a group comprising PbTiO3 {PT}, PbZrO3 {PZ}, PbZrxTi(1-x)O3 {PZT}, PbSiO3 {PS}, Pb(Fe1/2Nb1/2)O3 {PFN}, Pb(Mg1/3Nb2/3)O3 {PMN}, Pb(Ni1/3Nb2/3)O3 {PNN}, or Pb(Zn1/3Nb2/3)O3 {PZN}, and combinations thereof.

In a preferred embodiment of the present disclosure, the lead-based perovskite is PbTiO3 {PT}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is PbZrO3 {PZ}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is PbZrxTi(1-x)O3 {PZT}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is PbSiO3 {PS}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is Pb(Fe1/2Nb1/2)O3 {PFN}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is Pb(Mg1/3Nb2/3)O3 {PMN}.

In a preferred embodiment of the present disclosure, the lead-based perovskite is Pb(Ni1/3Nb2/3)O3 {PNN},

In a preferred embodiment of the present disclosure, the lead-based perovskite is Pb(Zn1/3Nb2/3)O3 {PZN}.

In an embodiment of the present disclosure, the lead-based perovskite are used in anodes to make safe lithium-ion and sodium-ion batteries, particularly in applications where a high-energy density is preferred to a high-power delivery. Most viable use can be for portable electronics especially as camera batteries where a similar invention on alloying of Sn-based ATCO glass was proposed by the Fujifilm Celltec Co. in 1994.9 Another promising area is their use as safe high energy density anodes for making sodium-ion batteries, where few options exist for anode. There can be room for use of our invention alongside lead-acid batteries in automotive application. Also. They can be implemented in sodium-ion batteries landscape frequently envisioned as alternatives to Li-ion batteries due to cheap and abundant Na containing raw materials. Pb holds upto 4.4 Li (Li22Pb5) and 3.75 Na (Na15Pb4) while only 1 lithium can be held by 6 C atoms (LiC6) in commercial graphite anode. Volume expansions is absorbed by in-situ generated oxide matrix during the first irreversible cycle involving structure breakdown. Further, graphite anode cannot intercalate Na ions which prevents it from being used in sodium-ion batteries. Pervoskites can be used as anode for sodium-ion batteries with first charge capacity as high as 406 mAh/g. Advantage include easy synthesis and extreme ambient stability unlike organic-inorganic lead halide counterparts or PX-PbTiO3 phases. Besides, these phases are weatherproof, and non-toxic as compared to pristine lead metal or its oxides used long back in charge storage. The use of tin necessitates an amorphous structure aimed at a smooth charge-discharge profile (to avoid Sn aggregation) for efficient charge storage which we think may not be a stringent condition for our case.

In a non-limiting embodiment of the present disclosure, the lead-based perovskite is prepared by a solid-state route.

In a non-limiting embodiment of the present disclosure, the lead-based perovskite is prepared by a solution combustion route.

PbTiO3 and PbZrO3 were selected as target materials to test the hypothesis of charge storage in Pb containing simple ABX3 and mixed A(BB?)X3 perovskites. Solid-state synthesis and wet solution combustion synthesis routes were employed. Respective oxide precursors were used in solid-state synthesis. The final calcination was performed in air ambience at 500-1000 oC for 12-24 h with intermittent grinding. For solution combustion synthesis, respective metal nitrate precursors were used as oxidizer along with glycine as oxidizer maintaining the oxidizer to fuel ratio of 1:1. The calcination was conducted from 300-500 oC for 1-6 h. Phase analysis was performed using X-Ray Diffraction performed (at 25 oC) using a Panalytical instrument (with Cu Ka source). Figure 1 shows the refinement performed using GSAS software with reasonable goodness of fit. PbTiO3 and PbZrO3 crystalized in tetragonal and orthorhombic structures respectively.

The active material, combustion/ solid-state synthesized PbTiO3 and PbZrO3, was hand mixed with carbon black (Super P) and aqueous binder (Sodium Carboxymethyl Cellulose, NaCMC) in a 80:10:10 ratio. Distilled water (500 µl/100mg of dry weight) was added and the resulting slurry was drop cast onto precut 12mm or 16mm coupons made from SS304 or battery grade Cu foils. After drying at 60 oC to remove water, the coatings were weighed and vacuum-dried in Buchi glass-oven at 120 oC overnight and transferred into Ar-filled glovebox (MBraun LabStar GmbH, O2 and H2O levels below 0.5 ppm). The coatings were used against respective M alkali metal using electrolytes acquired commercially or made in-house in 2032 type Coin cells or SS304 Swagelok cells. 1M LiPF6 dissolved in 1:1:3 v/v % of ethylene carbonate/propylene carbonate/dimethyl carbonate (EC/PC/DMC) was used as the lithium electrolyte (Chameleon Reagent). 1M NaPF6 or 0.5M KPF6 dissolved in 0.45:0.45:0.1 v/v % EC/PC/DMC was used as electrolytes for sodium and potassium-ion batteries. The current matched flow of one faraday charge, per unit mole active material, per 20 hours, which was around 4.4 mA/g and 3.87 mA/g for PbTiO3 and PbZrO3 respectively. The tests were performed in a Neware BTS4000 series battery cycler in a voltage window of 0.01 V to 2 or 2.5 or 3 V, without a rest time in between charge and discharge. PbO was also subjected to similar tests for comparison. Post cycling, the Swagelok were disassembled inside glovebox, the electrodes were washed using anhydrous DMC. The material was scratched from the washed electrode, dispersed in DMC and drop cast onto TEM grids inside the glovebox and dried in the antechamber overnight before examination.

Figure 2 depicts the electrochemical performance of combustion prepared PbTiO3¬ vs lithium. The underlying redox mechanism follows two-steps.

• First – The irreversible conversion step – where the first two electrons are used (Pb2+ to Pb0) as the parent structure slowly breaks down into constituent alloying element(s) (here, Pb) and MO2 (here, Li2O) plus oxides of any spectator non-alloying element (here, TiO2). MO2 oxide, like anti fluorite Li2O, is favoured to M due to high bond strength of M with oxygen. Due to growth of new phase, this step features as a long and flat two-phase voltage plateau at a value that is directly related to the stability of the parent structure (Figure 2a). Here, this happens at 0.74 V as compared to the 1.4 V flat profile for PbO, which indicates the PbO framework is more stable than the PbTiO3 structure. Absence of the 0.74V discharge peak in later cycles rules out reformation of PbTiO3 at the end of charge. Pb particles are clearly observed as cuboidal blocks of a size bigger than pristine PbTiO3 (Figure 2e and 2f). This indicates as the Pb particles form, they also aggregate and are electrochemically active evidenced by sharp dQ/mdV peaks (Figure 2c). The aggregates either reach a critical size now as the structure collapses, or later, after few (de)alloying reactions. The SAED patterns in Figure 2d further confirms large Pb particles (spots) along with polycrystalline Li2O and TiO2 matrix (rings). Electrolyte reduction in the formation cycle may also merge with this flat step justifying the slightly higher than 2 electron count. Aggregate formation from sharper dQ/mdV profiles occur gradually later in cycling for Sn based materials. At these peaks, co-existence of two phases having different volumes lead to microcrack, electrode delamination and capacity fade. Inactive MO2 oxide matrix generated in-situ during first step pins alloying element, restricts extreme aggregation and provides an elastic-cushion for checking large volume expansion typical for alloying reactions (more spectator ion - less aggregation - less volume change – less microcrack – less delamination – better capacity retention).
• Second – The reversible (de)alloying step – wherein the alloying element reversibly stores M forming intermetallic compounds. The compounds may (not) follow the equilibrium phase diagram. Two intermediate phases, most likely LiPb and Li2.6Pb, form reversibly as indicated from pairs of 0.55 V/0.64 V and 0.38 V/0.48 V peaks (Figure 2c). Li4.4Pb forms at the end of first discharge. This is confirmed by almost accurate 4.4 electron count after 2 electron from Pb(II) – Pb(0) reduction (Figure 2a). This reversible step is 410 mAh/g long for first charge and fades to 200 mAh/g by 70 cycles (Figure 2b). This fade could be due to sharp dQ/mdV peaks made from two phases with different volume. Once critical Pb size is reached, the dQ/mdV plots stabilize. As dQ/mdV plots remain unchanged, the critically sized Pb are delivered at the end of rupture reaction.

The concept of using perovskites was extended to sodium-ion batteries. Sometimes, first and second steps merge, i.e. conversion and alloying reactions coincide. In addition to Na/K metal’s low voltage with respect to Li, this merger could be from powerful tendency to alloy at its respective voltage drives the onset of initial conversion (and framework rupture). The rupture may not happen without presence of alloying element. In case of Na, there are two plateaus during discharge (total 7.5 electrons), one at 0.17 V likely from framework collapse and another at 0.03 V probably from alloying reaction as described in the second step (Figure 3c). However, during the first charge, four peaks indicate sequential dealloying of end phase formed at end of first discharge - Na15Pb4 (0.18 V) dealloys to Na9Pb4/Na5Pb2 (0.24 V), then NaPb (0.44 V), and finally to NaPb3 (0.55 V). After first cycle, 0.18 V dealloying charge peak merges with next peak, while discharge alloying peaks appear. The region near 1.5 V stores charge reversible for initial few cycles. This could from Na (de)insertion in TiO2 matrix as PX-PbTiO3. The capacity fade upon cycling can be due to damage of TiO2 by Na insertion, or the coarsening of Pb particles due to (de)alloying reactions that further mutilates TiO2 affecting its Na insertion properties. The reversible first charge capacity was 406 mAh/g for full 2.5 V window and 275 mAh/g for restricted 0.8 V window.

Upon application of perovskites to potassium-ion batteries, only one reduction plateau was observed (0.08 V, Figure 3d) yielding a first discharge capacity (for K-ion) of 450 mAh/g (or 5 electrons). This exceeds 2 electrons needed for framework rupture. Disregarding minor parasitic reactions, this confirms the alloying reaction overlaps with the rupture reaction at 80 mV. In the later cycles, new peaks evolve below 0.8 V which hint at possible KxPb phases (Figure 3d). 0.42 V discharge peak could be from the formation of K10Pb48, while the 0.6 V and 0.85 V peaks during charge are from K4Pb9 and Pb phase formation. Sharp discharge peak at 1.16 V may be from electrolyte reaction with Pb metal that is born at 0.8 V during charge. Alternately, alongwith the 1.6 V charge peak, Pb to PbO conversion reaction could be triggered as PbO to Pb happens at 1.12 V (Figure 3d). These side events contribute to higher reversible capacity (first charge) of around 178 mAh/g upto 3 V (theoretical capacity for KPb alloying is 130 mAh/g). Under 0.8 V, 55 mAh/g is seen (Figure 3b). An alternate hypothesis is reversible K-TiO2 insertion in this region or a mixture of both Pb conversion and TiO2 insertion. Whatever be the case may be, one thing is clear - the capacity delivered in the above region remains same (around 130 mAh/g) for all alkali ions indicating the same mechanism is in play.

For Sn-based compounds, amorphous morphology restricts Sn aggregation and subsequent sharp dQ/mdV where the existence of two phases results in capacity fade. To verify charge storage is independent of particle size or synthesis route, the electrochemical performance solid-state synthesized PbTiO3 and PbZrO3 were tested vs lithium and sodium (Figure 4). Both the phases behave similarly as expected with alloying reactions following initial rupture reaction. As expected, PbTiO3, due to lower molecular weight, showed higher reversible capacity than PbZrO3 (Figure 4a). Solid-state made PbTiO3 delivered less capacity than combustion made PbTiO3 from larger particle size. Rupture reaction for PbTiO3 is 56 mV higher than PbZrO3, indicating PbTiO3’s higher stability. Absence of this peak in later cycles rules out reformation of the starting perovskite structure at charge end-point. For sodium-ion case, PbZrO3 rupture and alloying reaction match as, like in case of Li (Figure 4c), the rupture reaction for Na for PbZrO3 is further pulled down. PbZrO3 delivered a reversible capacity of 65 mAh/g (Figure 4b). However, the first charge offers four peaks indicating four alloy formation during Na-Pb (de)alloying reaction as discussed previously.

Pb-based compounds have been extensively used as lead-acid accumulators in automobiles and inverters worldwide. Pb-acid batteries offer a recycling efficiency as high as 99%, a value that is even higher than that of tires. Both in elemental form or as oxides, the alloying reaction of Pb with Li, Na and K is well established. In the perovskite structure, Pb is non-toxic, and we propose such compounds as a safe lead box for extensive access to Pb-alloying reaction in high voltage, high energy density non-aqueous Li-ion or Na-ion batteries for use alongside aqueous lead-acid batteries.

It is to be understood that the foregoing descriptive matter is illustrative of the disclosure and not a limitation. While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. Those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Similarly, additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein.

Descriptions of well-known/conventional methods/steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above-described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the following examples should not be construed as limiting the scope of the embodiments herein.
Examples:
Example 1:
PbTiO3 and PbZrO3 were selected as target materials to test the hypothesis of charge storage in Pb containing simple ABX3 and mixed A(BB?)X3 perovskites. Solid-state synthesis and wet solution combustion synthesis routes were employed. Respective oxide precursors were used in solid-state synthesis. The final calcination was performed in air ambience at 500-1000 oC for 12-24 h with intermittent grinding. For solution combustion synthesis, respective metal nitrate precursors were used as oxidizer along with glycine as oxidizer maintaining the oxidizer to fuel ratio of 1:1. The calcination was conducted from 300-500 oC for 1-6 h. Phase analysis was performed using X-Ray Diffraction performed (at 25 oC) using a Panalytical instrument (with Cu Ka source). Figure 1 shows the refinement performed using GSAS software with reasonable goodness of fit. PbTiO3 and PbZrO3 crystalized in tetragonal and orthorhombic structures respectively.

The active material, combustion/ solid-state synthesized PbTiO3 and PbZrO3, was hand mixed with carbon black (Super P) and aqueous binder (Sodium Carboxymethyl Cellulose, NaCMC) in a 80:10:10 ratio. Distilled water (500 µl/100mg of dry weight) was added and the resulting slurry was drop cast onto precut 12mm or 16mm coupons made from SS304 or battery grade Cu foils. After drying at 60 oC to remove water, the coatings were weighed and vacuum-dried in Buchi glass-oven at 120 oC overnight and transferred into Ar-filled glovebox (MBraun LabStar GmbH, O2 and H2O levels below 0.5 ppm). The coatings were used against respective M alkali metal using electrolytes acquired commercially or made in-house in 2032 type Coin cells or SS304 Swagelok cells. 1M LiPF6 dissolved in 1:1:3 v/v % of ethylene carbonate/propylene carbonate/dimethyl carbonate (EC/PC/DMC) was used as the lithium electrolyte (Chameleon Reagent). 1M NaPF6 or 0.5M KPF6 dissolved in 0.45:0.45:0.1 v/v % EC/PC/DMC was used as electrolytes for sodium and potassium-ion batteries. The current matched flow of one faraday charge, per unit mole active material, per 20 hours, which was around 4.4 mA/g and 3.87 mA/g for PbTiO3 and PbZrO3 respectively. The tests were performed in a Neware BTS4000 series battery cycler in a voltage window of 0.01 V to 2 or 2.5 or 3 V, without a rest time in between charge and discharge. PbO was also subjected to similar tests for comparison. Post cycling, the Swagelok were disassembled inside glovebox, the electrodes were washed using anhydrous DMC. The material was scratched from the washed electrode, dispersed in DMC and drop cast onto TEM grids inside the glovebox and dried in the antechamber overnight before examination.

Figure 2 depicts the electrochemical performance of combustion prepared PbTiO3¬ vs lithium. The underlying redox mechanism follows two-steps.

• First – The irreversible conversion step – where the first two electrons are used (Pb2+ to Pb0) as the parent structure slowly breaks down into constituent alloying element(s) (here, Pb) and MO2 (here, Li2O) plus oxides of any spectator non-alloying element (here, TiO2). MO2 oxide, like anti fluorite Li2O, is favoured to M due to high bond strength of M with oxygen. Due to growth of new phase, this step features as a long and flat two-phase voltage plateau at a value that is directly related to the stability of the parent structure (Figure 2a). Here, this happens at 0.74 V as compared to the 1.4 V flat profile for PbO, which indicates the PbO framework is more stable than the PbTiO3 structure. Absence of the 0.74V discharge peak in later cycles rules out reformation of PbTiO3 at the end of charge. Pb particles are clearly observed as cuboidal blocks of a size bigger than pristine PbTiO3 (Figure 2e and 2f). This indicates as the Pb particles form, they also aggregate and are electrochemically active evidenced by sharp dQ/mdV peaks (Figure 2c). The aggregates either reach a critical size now as the structure collapses, or later, after few (de)alloying reactions. The SAED patterns in Figure 2d further confirms large Pb particles (spots) along with polycrystalline Li2O and TiO2 matrix (rings). Electrolyte reduction in the formation cycle may also merge with this flat step justifying the slightly higher than 2 electron count. Aggregate formation from sharper dQ/mdV profiles occur gradually later in cycling for Sn based materials. At these peaks, co-existence of two phases having different volumes lead to microcrack, electrode delamination and capacity fade. Inactive MO2 oxide matrix generated in-situ during first step pins alloying element, restricts extreme aggregation and provides an elastic-cushion for checking large volume expansion typical for alloying reactions (more spectator ion - less aggregation - less volume change – less microcrack – less delamination – better capacity retention).
• Second – The reversible (de)alloying step – wherein the alloying element reversibly stores M forming intermetallic compounds. The compounds may (not) follow the equilibrium phase diagram. Two intermediate phases, most likely LiPb and Li2.6Pb, form reversibly as indicated from pairs of 0.55 V/0.64 V and 0.38 V/0.48 V peaks (Figure 2c). Li4.4Pb forms at the end of first discharge. This is confirmed by almost accurate 4.4 electron count after 2 electron from Pb(II) – Pb(0) reduction (Figure 2a). This reversible step is 410 mAh/g long for first charge and fades to 200 mAh/g by 70 cycles (Figure 2b). This fade could be due to sharp dQ/mdV peaks made from two phases with different volume. Once critical Pb size is reached, the dQ/mdV plots stabilize. As dQ/mdV plots remain unchanged, the critically sized Pb are delivered at the end of rupture reaction.

The concept of using perovskites was extended to sodium-ion batteries. Sometimes, first and second steps merge, i.e. conversion and alloying reactions coincide. In addition to Na/K metal’s low voltage with respect to Li, this merger could be from powerful tendency to alloy at its respective voltage drives the onset of initial conversion (and framework rupture). The rupture may not happen without presence of alloying element. In case of Na, there are two plateaus during discharge (total 7.5 electrons), one at 0.17 V likely from framework collapse and another at 0.03 V probably from alloying reaction as described in the second step (Figure 3c). However, during the first charge, four peaks indicate sequential dealloying of end phase formed at end of first discharge - Na15Pb4 (0.18 V) dealloys to Na9Pb4/Na5Pb2 (0.24 V), then NaPb (0.44 V), and finally to NaPb3 (0.55 V). After first cycle, 0.18 V dealloying charge peak merges with next peak, while discharge alloying peaks appear. The region near 1.5 V stores charge reversible for initial few cycles. This could from Na (de)insertion in TiO2 matrix as PX-PbTiO3. The capacity fade upon cycling can be due to damage of TiO2 by Na insertion, or the coarsening of Pb particles due to (de)alloying reactions that further mutilates TiO2 affecting its Na insertion properties. The reversible first charge capacity was 406 mAh/g for full 2.5 V window and 275 mAh/g for restricted 0.8 V window.

Upon application of perovskites to potassium-ion batteries, only one reduction plateau was observed (0.08 V, Figure 3d) yielding a first discharge capacity (for K-ion) of 450 mAh/g (or 5 electrons). This exceeds 2 electrons needed for framework rupture. Disregarding minor parasitic reactions, this confirms the alloying reaction overlaps with the rupture reaction at 80 mV. In the later cycles, new peaks evolve below 0.8 V which hint at possible KxPb phases (Figure 3d). 0.42 V discharge peak could be from the formation of K10Pb48, while the 0.6 V and 0.85 V peaks during charge are from K4Pb9 and Pb phase formation. Sharp discharge peak at 1.16 V may be from electrolyte reaction with Pb metal that is born at 0.8 V during charge. Alternately, alongwith the 1.6 V charge peak, Pb to PbO conversion reaction could be triggered as PbO to Pb happens at 1.12 V (Figure 3d). These side events contribute to higher reversible capacity (first charge) of around 178 mAh/g upto 3 V (theoretical capacity for KPb alloying is 130 mAh/g). Under 0.8 V, 55 mAh/g is seen (Figure 3b). An alternate hypothesis is reversible K-TiO2 insertion in this region or a mixture of both Pb conversion and TiO2 insertion. Whatever be the case may be, one thing is clear - the capacity delivered in the above region remains same (around 130 mAh/g) for all alkali ions indicating the same mechanism is in play.

For Sn-based compounds, amorphous morphology restricts Sn aggregation and subsequent sharp dQ/mdV where the existence of two phases results in capacity fade. To verify charge storage is independent of particle size or synthesis route, the electrochemical performance solid-state synthesized PbTiO3 and PbZrO3 were tested vs lithium and sodium (Figure 4). Both the phases behave similarly as expected with alloying reactions following initial rupture reaction. As expected, PbTiO3, due to lower molecular weight, showed higher reversible capacity than PbZrO3 (Figure 4a). Solid-state made PbTiO3 delivered less capacity than combustion made PbTiO3 from larger particle size. Rupture reaction for PbTiO3 is 56 mV higher than PbZrO3, indicating PbTiO3’s higher stability. Absence of this peak in later cycles rules out reformation of the starting perovskite structure at charge end-point. For sodium-ion case, PbZrO3 rupture and alloying reaction match as, like in case of Li (Figure 4c), the rupture reaction for Na for PbZrO3 is further pulled down. PbZrO3 delivered a reversible capacity of 65 mAh/g (Figure 4b). However, the first charge offers four peaks indicating four alloy formation during Na-Pb (de)alloying reaction as discussed previously.

Numbered Embodiments
The disclosure is further elucidated by reference to the numbered embodiments herein.

1. A lead-based perovskite with PbXO3, wherein X is selected from a group comprising titanium, zirconium, silicon, iron, niobium, nickel or zinc, tantalum, germanium, or tin and combinations thereof.
2. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is selected from a group comprising PbTiO3 {PT}, PbZrO3 {PZ}, PbZrxTi(1-x)O3 {PZT}, PbSiO3 {PS}, Pb(Fe1/2Nb1/2)O3 {PFN}, Pb(Mg1/3Nb2/3)O3 {PMN}, Pb(Ni1/3Nb2/3)O3 {PNN}, or Pb(Zn1/3Nb2/3)O3 {PZN}, and combinations thereof.
3. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbTiO3 {PT}.
4. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbZrO3 {PZ}.
5. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbSiO3 {PS}.
6. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbZrxTi(1-x)O3 {PZT}.
7. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Fe1/2Nb1/2)O3 {PFN}.
8. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Mg1/3Nb2/3)O3 {PMN}.
9. The lead-based perovskite of embodiment 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Ni1/3Nb2/3)O3 {PNN}.
10. The lead-based perovskite is preferably lead-based perovskite is Pb(Zn1/3Nb2/3)O3 {PZN}.
11. The lead-based perovskite of any of preceding embodiments are used in anodes to make lithium-ion, potassium-ion and sodium-ion batteries
12. An energy storage device comprising anode and cathode, wherein the anode is composed of lead-based perovskite(s) of embodiments 1-10.
13. Ion batteries are composed of lead-based perovskite(s) of embodiments 1-10.
14. The ion batteries of embodiment 13, wherein the ion batteries are selected from a group comprising lithium- ion batteries, sodium- ion batteries, or potassium-ion batteries.
15. Use of Pb alloying center in anode for rechargeable lithium-, sodium-, and potassium-ion batteries for the lead-based perovskites of embodiments 1-10.
,CLAIMS:1. A lead-based perovskite with PbXO3, wherein X is selected from a group comprising titanium, zirconium, silicon, iron, niobium, nickel or zinc, tantalum, germanium, or tin and combinations thereof.
2. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is selected from a group comprising PbTiO3 {PT}, PbZrO3 {PZ}, PbZrxTi(1-x)O3 {PZT}, PbSiO3 {PS}, Pb(Fe1/2Nb1/2)O3 {PFN}, Pb(Mg1/3Nb2/3)O3 {PMN}, Pb(Ni1/3Nb2/3)O3 {PNN}, or Pb(Zn1/3Nb2/3)O3 {PZN}, and combinations thereof.
3. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbTiO3 {PT}.
4. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbZrO3 {PZ}.
5. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbSiO3 {PS}.
6. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is PbZrxTi(1-x)O3 {PZT}.
7. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Fe1/2Nb1/2)O3 {PFN}.
8. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Mg1/3Nb2/3)O3 {PMN}.
9. The lead-based perovskite as claimed in claims 1, wherein the lead-based perovskite is preferably lead-based perovskite is Pb(Ni1/3Nb2/3)O3 {PNN}.
10. The lead-based perovskite is preferably lead-based perovskite is Pb(Zn1/3Nb2/3)O3 {PZN}.
11. The lead-based perovskite as claimed in any of preceding claim are used in anodes to make lithium-ion, potassium-ion and sodium-ion batteries
12. An energy storage device comprising anode and cathode, wherein the anode is composed of lead-based perovskite(s) as claimed in claims 1-10.
13. Ion batteries are composed of lead-based perovskite(s) as claimed in claims 1-10.
14. The ion batteries as claimed in claim 13, wherein the ion batteries are selected from a group comprising lithium- ion batteries, sodium- ion batteries, or potassium-ion batteries.
15. Use of Pb alloying center in anode for rechargeable lithium-, sodium-, and potassium-ion batteries for the lead-based perovskites as claimed in claims 1-10.