PRECURSOR OF ELECTRODE ACTIVE MATERIAL COATED WITH METAL AND METHOD OF PREPARING THE SAME [TECHNICAL FIELD] 5 The present invention relates to a precursor of an electrode active material coated with a metal and a method of preparing the same. More partic~tlarly, the present invention relates to a precursor of an electrode active ~naterial for a lithium secondary battery, in which a metal material that is ionizable tl~ough electrolytic decomposition is uniformly coated on a surface of a primary precursor formed of a 10 transition metal hydrate and a method of preparing the salne. [BACKGROUND ART] As mobile device technology continues to develop and demand therefor collti~lucs to increase, demantl for secondary batteries as energy sources is rapidly increasing. Amo~lgth ese secondary batteries, research on lithium secondary batteries, 15 which exhibit high energy density and discharge voltage, has been under~vay and such lithium secondary batteries are commercially available and widely used. Lithium secondary batteries have long electrode lifespan and excellent liigh-speed charge and discharge efficiency and thus are used lllost widely. In general, a lithium secondary battery has a structure in wltich an electrode assembly, which includes: a cathode i~lcludinga lithium transition metal oxide as an 5 electrode active material; an anode including a carbon-based active material; and a polyolefin-based porous separator disposed between the cathode and the anode, is itnpregtlated with a lithium salt-containing non-aqueous electrolyte, such as LiPF6 or the like. In this regard, a lithium cobalt-based oxide, a lithiutn manganese-based oxide, 10 a lithiutn nickel-based oxide, a lithiutn cotllposite oxide, and the like are mainly used as cathode active materials, and a carbon-based material is nlainly used as all anode active material. Lithium ions of a cathode active material arc deitltercalated and then intercalated into a carbon layer of a11 anode during charge, the lithium ions of the carbon layer are deitltercalated atid then intercalated into the cathode active nlaterial duriug 15 discharge, and a non-aqueous electrolyte serves as a medium through which lithiutll ions migrate between the anode and the cathode. Such lithium secondary batteries basically require stability within operating voltage ranges of a battery and the ability to transfer ions at a sufficiently rapid rate. However, in secondary batteries using a fluorine (F)-containing electrolyte and a carbon material as an anode active material, as a charge and discharge process progresses, metal conlponents of a cathode active material are eluted into an electrolyte and lithiu~n is deposited onto a surface of a carbon nlaterial and, accordingly, the 5 electrolyte decomposes at the carbon material. Such deposition of metal components and decomposition of an electrolyte more severely occur when a secondary battery is stored at high temperature, which results in reduction in battery relnaining capacity and recovery capacity. Meanwhile, a lithium transition metal oxide used as a cathode active material 10 has low electrical conductivity, and reaction between the lithium transition metal oxide and an electrolyte is accelerated at high telnperaturc, generating a by-product that increases resistance of a cathode, which results in drastic reduction in storage lifespan at high temperature. To address these problenls of a cathode and an anode, the related art discloses a 15 technology for coating or treating a surface of a cathode or anode active material with a predetermined material. For example, Japanese Patent Application Laid-open No. 2000-12026 discloses a method of coating an oxide of a metal such as Ni, Co, Cu, Mo, W, or the like on a surface of a carbon-based anode active material. In addition, as a method of coating a -3- cathode active material with a conductive nlaterial to reduce resista~lce of a contact interface between the cathode active material and an electrolyte or a by-product generated at high temperature, a neth hod of coating a cathode active material wit11 a conductive poly~neris known. 5 In addition, Korean Patent Application Publication No. 2003-0088247 discloses a method of preparing a cathode active material for a lithiu~n secondary battery, including: (a) surface-treating a metal-containing source by adding the metalcontaining source to a doping elerne~lt-co~ltainincgo ating solution (wherein the metalcontaining source is a material containing a metal selected fiom the group consisting of 10 cobalt, tnanganese, nickel, and co~nbinations thereof and excluding lithium); (b) preparing an active material precursor by drying the surface-treated metal-containing source; and (c) mixing the active nlaterial precursor and the lithium-containing source and heat-treating the resulting mixturc. However, a water-soluble ~naterial cannot be used in coating of a calcined 15 electrode active material and, when an oxide is used, it is difficult to smoothly coat an already synthesized nlaterial with the oxide. The related art discloses coating with OH groups, but it is difficult to form a uniform fill11 using this method, and only restrictive materials in accordance with pH and the like rnay be used and thus there is li~nitationi n coating conlposition. -4- Therefore, there is a high need to develop a tecl~nologyt hat may fi~ndatnentally address these problems. [DISCLOSURE] [TECHNICAL PROBLEM] 5 Therefore, the present invention has been made to solve the above problems and other technical probletns that have yet to be resolved. As a result of a variety of intensive studies and various experiments, the inventors of the present invention discovered that, when coating a metal material on a primary precursor formed of a transition metal hydrate through electrolytic 10 decomposition, the coating material does not permeate the inside of the primary precursor and fornis a uniform film on a surface thereof in an electrode active material synthesis process, thus completing the present invention. Therefore, it is an object of the present invention to provide an electrode active tnaterial precursor tmifonnly coated with a nletal nlaterial through electrolytic 15 decotnposition and a method of preparing the same. [TECHNICAL SOLUTION1 In accordance with one aspect of the present invention, provided is a precursor of an electrode active material for a lithium secondary battery, in which a nletal material that is ionizable thong11 electrolytic deconlposition is uniforlnly coated on a surface of a primary precursor formed of a transition metal llydrate. 5 In one specific embodiment, the electrolytic deconlposition may be inlplernented such that the metal material is ionized in an aqueous acid solution, forming an internlediate, followed by reduction. In particular, when electricity is applied between positive (+) and negative (-) electrode plates using a metal material to be coated, in a state of being immersed in an 10 aqueous acid solution such as an aqueous sulfi~rica cid solution or the like, a metal of the nletal material receives electrons to be ionized into a metal ion at the positive (+) electrode, the nmetal ion reacts with sulfuric acid ions of tile aqueous sulfi~ric acid solution to form a nletal salt as an intermediate, and the tnetal salt receives electrons from the negative (-) electrode to be reduced into the metal. The metal obtained by 15 reduction is adsorbed onto primary precursor particles and, accol.dingly, the nletal may be coated on the prinlarp precursor particles. The intennediate formed in the electrolytic deconlposition process may, in particular, be a metal salt, for example, a sulfate or a nitrate, but ertlbodiments of the present invention are not limited thereto. That is, various materials in the form of acid salts may be used. When coating the psimary precursor tlxougl~ electrolytic decot~lposition as described above, a metal form is coated on the primary precursor and thus has a 5 different syntl~csist emperature than -OH or -0OH and, accordingly, the metal form does not permeate the inside of the primary precursor even through a subsequent calcination process and forms a surface different than the inside thereof, wl~ereby a uniform film may be fonned. In addition, electrolytically decomposable metals are not affected by pI-I and 10 the like and thus coating of various metal cotl~positionsi s possible. In one specific embodiment, the metal material may be a material containing at least one element selected from the group consisting of an electrolytically decon~posabletr ansition metal, P, and Al. In particular, the transition metal may be at least one elenlent selected fro111 the group consisting of Ni, Co, Mn, Fe, Sn, Mo, Nd, Zr, and Zn. 15 However, when coating a metal inaterial having high oxidation potential, such as Mn, electrolytic decomposition is not easy to implement and an oxide such as Mn02 is produced and thus desired resulting products may not be obtained. Thus, in one specific embodiment, the electrolytic deconlposition may be performed using a catalyst. In particular, the catalyst inay be at least one selected from the group consisting of a ZtiCl2-based catalyst, a CoCl2-based catalyst, a MnC12-based catalyst, a NiCl2-based catalyst, and a SnC12-based catalyst. More particularly, a ZnC12-based catalyst may be used. In one specific embodiment, a coating thichess of the metal material may be 5 0.1 prn to 1 pm. When the coating thickness is less than 0.1 pm, it may be difficult to achieve uniform coating and desired effects such as desired electrical conductivity and tlie like through metal coating may not be obtained. On the other hand, intercalation and deintercalation of lithium ions may be interfered with if the coating thickness exceeds 1 pnl. 10 I11 addition, the amount of the metal material may be 0.01% to 5% based on a total weight of the precursor of the electrode active material. 'The metal material may be completely or partially coated on the surface of the primary precursor. Preferably, the tiietal material may be conlpletely coated on tlie surface of the primary precursor. When the amount of the metal material is less than 0.01% based on the total 15 weight of the precursor of tlie electrode active material, probleiils occurring due to reaction between a cathode active niaterial and an electrolyte may not be prevented and excellent electrical conductivity may not be obtained. When the amount of the tnetal material exceeds 5%, the amount of the electrode active material relatively decreases and thus capacity niay be reduced. -8- In one specific embodiinent, the primary precursor may be a nlaterial represented by Fornlula 1 below: wherein 0.5 A metal hydroxide, M(O130.6)2 where M=N~O.~M~I~.ZaCsO aU .p~r,im ary 10 precursor was calcined without plating through electrolysis to prepare LiNio.6Mno.2Coo.20a2s a cathode active material for lithium secondary batteries. Observation of prepared cathode active materials using SEM and EDX analysis thereof 15 The Ni-based cathode active materials prepared according to Example 1 and Comparative Example 1 were observed using a scanlling electron inicroscope (SEM) and obsel-vation results are shown in FIGS. 1 and 2. In addition, energy-dispersive Xray spectroscopy (EDX) analysis results of the cathode active material of Example 1 are shown ia Table 1 below, and Region 1 and Rcgion 2 SIIO\VII in Table 1 are illltlstrated in the SEM cross-sectional image of the cathode active material of Example 1 of FIG. 3. [Table I] 5 Referring to FIG. 1, it can be cotifirnied that Co is smoothly coated on a surface of the lithium nickel cobalt manganese oxide of Example 1. In addition, referring to FIG. 3 and Table 1, it can be confirmed that the amount of Co on the surface of the cathode active material is greater than that inside the cathode active material. This is because Co and the primary precursor inside the cathode active material have 10 different synthesis temperatures and thus, even after calcitiatioii, Co does not permeate into the primary precursor, but forms a surface different than the inside thereof. Although the preferred embodiments of the presetit inveation have been disclosed for illustrative purposes, those skilled iu the art will appreciate that various modifications, additions and substitutions are possible, without departing from the 15 scope and spirit of the invention as disclosed in the accompanying clainis. Weight % Region 1 Region 2 Co 25.1 22.4 Mn 14.8 16.8 Ni 60.2 60.8 [INDUSTRIAL APPLICABILITY1 As described above, in a precursor or an electrode active material according to the present invention, even though a pri~narpp recursor coated with a metal material is subjected to a subsequent sy~ltliesisp rocess, the coating material does not permeate the 5 inside of the electrode active material, but remains on a surface thereof, thereby forming a uniforln metal coated film. In addition, the precursor of the electrode active material may be coated with various metals. In addition, according to a method of preparing the precursor of an electrode active material, a large amount of a primary precursor may be coated with a uniform 10 amount of a metal material and may be coated with materials that cannot be coated though co-precipitation. we claims:- [Claim 1] A precursor of an electrode active material for a lithium secondary battery, in xvhich a metal material ionizable through electrolytic decomposition is uniformly coated on a surface of a primary precursor co~nprising a transition nletal 5 hydrate. [Claim 21 The precursor according to claim 1, wherein the electrolytic decomposition is performed such that the metal material is ionized in an aqueous acid solution, forming an intermediate, followed by reduction. KClaini31 The precursor according to claim 2, wherein the intermediate is a 10 metal salt. [Claim 41 The precursor according to claim 3, wherein the metal salt is a sulfate or a nitrate. [Clai~n5 1 The precursor according to claim 1, wherein the electrolytic deco~npositionis performed using a catalyst. 15 [Claim 61 The precursor according to claim 5, wherein the catalyst is at least one selected fkom the group consisting of a ZnCI2-based catalyst, a CoCl2-based catalyst, a MnClz-based catalyst, a NiCl2-based catalyst, and a SnC12-based catalyst. [Claim 71 The precursor according to clainl 1, wherein the primary precursor is represented by Fornlula 1 below: wherein 0.5