I'RECURSOR FOR PREPARING LITHIUM COMPOSITE TRANSITION METAL OXIDE, METHOD FOR PREPARING THE PRECURSOR, AND LITHIUM COMPOSITE TRANSITION METAL OXIDE The present invention relates to a precursor for preparing a lithium conlposite transition metal oxide, a method for preparing the precursor, and a lithium conlposite transition nletal oxide. Technological development and increased demand for mobile devices have led to rapid increase in the demand for secondary batteries as energy sources. Anlong such secondary batteries, lithium secondary batteries having high energy density and higli discharge voltage have been extensively studied and are now commercially available and widely used. Lithium secondary batteries are the most conunonlp used 15 due to superior electrode life and high rapid-cliarge/discharge efficiency. Lithium-containing cobalt oxide (LiCoOz) is typically used as a cathode active material for lithium secondary batteries and use of lithium-containing manganese oxides -1- sucl~a s LiMn02 having a layered crystal structure and LiMn204 having a spinel crystal structure and lithium-containing nickel oxides (LiNi02) is also under consideration. A~llong such cathode active materials, LiCo02 is cunently widely used due to superior general properties such as excellent cycle characteristics, but has disadvantages 5 such as low safety and high cost due to limited resource availability of cobalt as a raw material. Lithiutn nickel-based oxides such as LiNiO2 have problems such as high manufacturing cost, swelling caused by gas generation in batteries, low chemical stability, and high pH although they are cheaper than LiCoO2 and exhibit high discharge capacity when charged to 4.25V. 10 Lithium manganese oxides such as LiMnO2 and LiM11204 have attracted a great deal of attention as cathode active materials capable of replacing LiCo02 due to advantages such as natural abundance of the raw materials and the use of eco-friendly manganese. Among these litliulium manganese oxides, LiMnz04 has advantages such as relatively low price and high output, but has lower energy density than LiCoO2 and 15 three-co~nponenat ctive materials. When Mn in LiMn204 is partially replaced by Ni to overcome such disadvantages, an operating potential of about 4.7 V, higher than the original operating potential of about 4 V, is achieved. A spinel lilaterial having a conlpositio~l of Lil+,NixMt~2,04.,(02 a2 0.1, 0.42 x2 0.5, 02 z2 0.1) has a high potential and, as such, is ideally suited for use as a cathode active material for middle or large-scale lithium ion batteries such as electric vehicles that require high energy and high output perfor~nance. Lithium transition metal active materials containing two or more types of 5 materials such as Ni and Mn are not easily synthesized by simple solid-state reaction. In a know11 technique, a transition metal precursor prepared by coprecipitation or the like is used as a precursor to prepare such lithium transition metal active materials. However, a transition metal precursor for preparing the spinel material is not easily syntl~esized by coprecipitation since the transition metal precursor has a high 10 content of Mn such that oxidation easily occurs due to oxygen dissolved in an aqueous transition metal solution. Tli~~sa, lithium composite transition metal oxide having satisfactory perfor~nance and a precursor for preparing such a lithium composite transition metal oxide have yet to be developed. Therefore, the present invention has been made to solve the above and other technical problems that have yet to be solved. -3- As a result of intensive studies and various experinlents, the present i~lventors discovered that, when a composite transition metal compound having a specific composition and a Mn content of 60 to 85 mol% is prepared by coprecipitation in a state in which a reductant is added, oxidation of Mn is prevented and the sphericity of the 5 composite transition metal conlpound is increased while it is possible to synthesize a precursor having more uniform granularity and also that a secondary battery including a lithiu~ll composite transition metal oxide prepared using the precursor as a cathode active material exhibits increased initial discharge capacity and eficiency and improved output and service life characteristics. The present invention has been completed 10 based on this discovery. I11 accordance with the present invention, the above and other objects can be accomplished by the provision of a transition metal precursor including a composite transition metal compound having a composition represented by For~ntla(1 ) and a Mn 15 content of 60 to 85 mol%: where M is at least one selected fro111 the group consisting of Ti, Co, Al, Cu, Fe, Mg, B, Cr, Zr, Zn and period I1 transition metals, and 0.15s as 0.3, 0s bs 0.1 and 0 A nickel-titanium-manganese composite transition metal precursor of Nio.25Tio.~Mno.7~(0Hw~-a\s) 2p repared in the same manner as Example 1, except that an aqueous transition metal solution was mixed with 20 mol% of sucrose. The average 5 particle diameter of the prepared nickel-titaniunl-nlangatlese conlposite transition metal precursor was 28 micrometers and the tap density thereof was 0.75 g/c~n3. SEM images of the precursors prepared in Example 1 and Comparative Example 1, which are shown in FIGS. 1 and 2, were captnred using an I:E-SEM 10 (Hitachi, S-4800 model). From FIGS. 1 and 2, it can be seen that the precursor of Example 1 prepared using 0.2 mol% of sucrose has more spherical particles due to improved cohesion of primary particles, as compared to the precursor of Comparative Example 1 prepared without mixing with sucrose. 15 Coin Cell Fabrication In Example 2 and Comparative Examples 3 and 4, respectively, the nickeltitanium- manganese composite transition metal precursors prepared in Example 1 and Comparative Examples 1 and 2 were mixed with Li2C03 in respective molar ratios according to the conlpositions of the precursors and Li2C03. Each mixture was heated at an elevation rate of 5'C/min and sintered at 950'~ for 10 hours to prepare a cathode active material powder of Li[Nio.~5Tio.o~&.71]204. The prepared cathode active material powder, a conductive nlaterial (Denka Black) and a binder (KF1100) were nlixed in a weight ratio of 95:2.5:2.5 to prepare a slurry. The slurry was uniformly applied to Al foil having a thickness of 20 pnl. Tile slulry-coated A1 foil was dried at 130'~to form a cathode for lithium secondary batteries. 10 A 2016 coin cell was fabricated using the formed cathode for lithium secondary batteries, a lithium metal foil as a counter electrode (anode), a polyethylene film (Celgard, thickness: 20 pn~)a s a separator, and a liquid electrolyte including 1M LiPFs dissolved in a solvent in which ethylene carbonate, dimethylene carbonate and diethy1 carbonate were mixed in a ratio of 1:2:1. Coin Cell Fabrication Each nickel-titanium-mlanganese composite transition metal precursor prepared it1 Example 1 was mixed with 110 mol% of Li~C03an d 5 11101% of NH4F, relative to the precursor, in a molar ratio according to the compositions of the precursor, Li2C03 and NH4F. Each ~nixturew as heated at an elevation rate of 50c/min and sintered at 950~' for 10 hours to prepare a cathode active material powder of Li1.1[ Nio.25Tio.o4M~o.711203.95F0.05. The prepared cathode active material powder, a collductive material (Denka 5 Black) and a binder (KF1100) were mixed in a weight ratio of 95:2.5:2.5 to prepare a sluliy. The slurry was uniformly applied to A1 foil having a thickness of 20 pm. The slurry-coated A1 foil was dried at 130'~ to form a cathode for lithium secondary batteries. A 2016 coin cell was fabricated using the formed cathode for lithium 10 secondary batteries, a lithium metal foil as a counter electrode (anode), a polyetl~ylene film (Celgard, thickness: 20 pm) as a separator, and a liquid electrolyte including 1M LiPF6 dissolved in a solverlt in which ethylene carbonate, dimethylene carbonate and dietliyl carbonate were mixed in a ratio of 1:2:1. 15 Initial Charge/Discharge Characteristics The characteristics of the cathode active material of each of the coin cells fabricated in Exanlples 2 and 3 and Con~parative Examples 3 and 4 were evaluated using an electrocl~e~~~anicaalylz er (Toyo System, Toscat 3100U) in a voltage range of 3.5 to 4.9 V. For battery estimation, charge/discharge capacity was measured in the voltage range of 3.5 to 4.9 V at an applied cul~ent of 0.1C. Discharge capacity and chargeldischarge efficiency results are shown in Table 1 below. Table 1 I Ex. 2 I 147.5 I I 143.2 97.1 I Sa~ilple I Ex. 3 I 147.3 I 143.8 I 97.6 I 5 It can be seen from Table 1 that batteries of Examples 2 and 3, in which 0.2 101% of sucrose was added to prepare the precursor, exhibited similar initial cltarge/discharge capacity and efficiency higher than those of Comparative Example 3 in which no reductant was added and Conlpavative Exatnple 4 in whicl1 an excessive amount of sucrose was added. It can also be seen that Comparative Exatnple 4 in 10 which an excessive amount of sucrose was added exhibited much lower initial charge/discharge capacity and efficiency than Comparative Example 3 in which no reductant was added. This is believed to be due to the fact that the content of transition metal in the precursor decreases as an excessive amount of reductant is added. Initial Charge Capacity (mAldg) 15 Service Life Characteristics lnitial Discharge Capacity (m Ahlg) Initial ChargelDiscllarge Efficiency (%) Each of the coin cells fabricated in Examples 2 and 3 and Comparative Examples 3 and 4 was charged/discharged 50 times at a current of 1.0 C and service life cl~aracteristicst hereof were evaluated. Evaluation results are shown in Table 2 below. Table 2 Service Life Characteristics I I 50tldlst Discharge Capacity (%) I I Camp. Ex. 4 I 91.7 I Ex. 2 Camp. Ex. 3 I Ex. 3 I 99.8 I 99.5 97.2 As can be seen from Table 2, batteries of Examples 2 and 3, in which 0.2 mol% of sucrose was added, exhibited similar discharge capacity of almost loo%, achieving superior service life characteristics to those of Comparative Example 3 in wliich no reductant was added and Comparative Example 4 in which an excessive aniount of sucrose was added. Particularly, it can be seen that Comparative Example 4 10 in which an excessive amount of sucrose was added exhibited much lower initial charge/discliarge capacity and efficiency than Comparative Example 3 in which no reductant was added. This is believed to be due to the fact that the content of transition ~netalin the precursor decreases as an excessive amount of reductant is added. Output Cliaracteristics Each of tl~e coin cells fabricated in Examples 2 and 3 and Comparative Examples 3 and 4 was discharged at a current of 2.0 C after being cl~argedldischargeda t a current of 0.1 C and output characteristics thereof were evaluated. Evaluation results are shown in Table 3 below. Table 3 0.1C Discharge Capacity (rn Alilg) I ~ o m p~. x . 4 1 110.6 I 100.2 I 90.6 I Ex. 2 Comp. Ex. 3 2C Discharge Capacity (m AhJg) As can be seen from Table 3, batteries of Examples 2 and 3, in which 0.2 Output Characteristics O.ICI2.OC (%) 143.2 141.8 Ex. 3 mol% of sucrose was added, exhibited similar output characteristics higher tllan those of 140.6 135.7 Comparative Example 3 in which 110 reductant was added and Comparative Exanlple 4 143.8 in which an excessive amount of sucrose was added. Particularly, it can be seen that 10 Comparative Example 4 in which an excessive anlount of sucrose was added exhibited 142.5 much lower initial chargeldischarge capacity and efficiency than Conlparative Example 99.1 3 in wl~icnl~o reductant was added. Tliis is believed to be due to the fact that the content of transition metal in the precursor decreases as an excessive anlount of redoctant is added. It will be apparent to those skilled in the art that various n~odifications and variations are possible in light of the above teaching without departing from the scope of the invention. [INDUSTRIAL APPLICABILITY] As is apparent fsom the above description, a transition metal precursor for preparing a lithium composite transition metal oxide according to the present invention is prepared by coprecipitation in a state in which a reductant is added to prevent oxidation of Mn. Therefore, it is possible to synthesize a colilposite transition metal compound having a specific co~npositiona nd a Mn content of 60 to 85 mol%, which 10 achieves higher sphericity and more uniform granularity. Pal-ticnlarly, when a saccharide reductant is used, the reductant call remain in a closed pore in the transition liietal precursol; providing effects of surface treatment with carbon. Therefore, it is also possible to improve electrochen~icalc haracteristics of the cathode active rilaterial after sintering. In addition, w11en a lithium composite transition metal oxide is prepared using the precursor prepared in the above manner, a secondary battery including the lithium coniposite tralisition metal oxide exhibits increased initial discharge capacity and efficiency and improved output and service life characteristics. WE CLAIM:- [claim 1 I A traasition metal precursor comprising a composite transition metal compound having a composition represented by Formula (1) and a Mn content of 60 to 85 mol%: where M is at least one selected from the group consisting of Ti, Co, Al, Cu, Fe, Mg, B, Cr and period I1 transition metals, 05 b5 0.1. and [Claim 21 The transition metal precursor according to claim 1, wl~ereinM is Ti or Al. [claim 31 The transition metal precursor according to claitn 1, wherein a is equal to or greater than 0.2 and equal to or less than 0.25. 15 [~laim41 The transition metal precursor according to clairn 1, wherein the Mn content is 70 to 80 mol%. [Claitn 51 The transition metal precursor according to claim 1, wherein x is equal to or greater than 0.2 and less than 0.5. [Claim 61 The transition metal precursor according to claim 1, wherein x is 5 equal to or greater than 0.3 and less than 0.5. [Claim71 The transition metal precursor according to claim 1, wherein an average particle diameter of the composite transition metal cotnpound is 4 to 20 micro~neters. [claim 81 The transitioll metal precursor according to claim 1 , wherein a tap 10 density of the composite transition metal compound is 0.8 to 2.5 g/cm3. [Claim 91 The transition metal precursor according to claim 1, wherein the composite transition metal conipound is prepared by coprecipitation in a state in which a basic substance and a reductant for preventing oxidation of Mn are added to an aqueous transition metal solution mixed with a transition metal-containing salt. 15 [Claim 101 The transition metal precursor according to claim 9, wherein the reductant is added in an amount of 0.01 to 10 mol% relative to the molar quantity of tlie aqueous transition metal solution. [Claim 111 The transition metal precursor according to claim 9, wherein the rednctant comprises at least one selected from the group consisting of hydrazine, oxalic acid, ascorbic acid and a saccharide material. [Claim 121 The transition metal precursor according to claim 11, wherein the 5 saccharide material comnprises at least one selected from the group consisting of fructose, sucrose, glucose, galactose, lactose, maltose, starch and dextrin. [Claim 131 The transition metal precursor according to claim 12, wherein the saccharide material comprises sucrose. [Claim 141 The transition metal precursor according to clai~n 9, wherein the 10 reductant conlprises a saccharide material and is present on the surface andlor inside of the transition metal precursor. [Claim 151 The transition metal precursor according to claim 9, wherein the reductant comprises a saccharide material and at least a part of the saccharide material is present in a closed pore formed in the transition metal precursor. 15 [Claim 161 The transition metal precursor according to claim 9, wherein the transition metal-containing salt comnprises sulfate and the basic ~naterial comprises sodium l~ydroxide. [Claim 171 The transition metal precursor according to claim 16, wherein the sulfate comprises at least one selected from the group consisting of nickel sulfate, titanium sulfate and manganese sulfate. [Claim 181 The transition metal precursor according to claim 1, wherein the 5 content of the composite transition metal compound is 30% by weight or higher, based on the total amount of the transition metal precursor. [claim 191 The transition metal precursor according to claim 18, wherein the content of the composite transition metal compound is 50% by weight or higher. [claim 201 A method for preparing the composite transition metal compound of 10 the transition metal precursor according to claim 1, the method comprising: (i) preparing an aqueous transition metal solution containing a transition metal salt for precursor preparation; (ii) mixing, with the aqueous transition metal solution, 0.01 to 10 mol% of a reductant relative to the molar quantity of the aqueous transitioil metal solution; and 15 (iii) adding a strong base to the aqueous transition metal solution mixed with the reductant to induce coprecipitation. [Claim 211 A lithium composite transition metal oxide prepared using the -33- tra~lsitiom~le tal precursor accordi~lgto claim 1. [~laim22 1 The lithium composite transition metal oxide according to claim 21, wherein the lithium con~positetr ansition metal oxide is surface-treated with carbon. [Claim 231 The lithium colllposite transition metal oxide according to claim 22, 5 wherein the carbon is derived from the reductant conlprising a saccharide material. [Claim 241 A lithium con~posite transition metal oxide having a composition represented by Fonnula (2) and a Mn content of 60 to 85 mol%: where M is at least one selected from the group consisting of Ti, Co, Al, Cu, 10 Fe, Mg, B, Cr and period I1 transition metals, A is a monoanion or dianion, 0.155 a5 0.3, 0.005s bs 0.1, -0.15 zs 0.1, and 0 ys 0.1. [Claip 251 The lithium composite transition metal oxide accordihg tp claim 24, wherein the lithium co:nposite transition metal oxide is surface-treated with carbon. [Claim 261 A cathode comprising the lithiu~nc omposite transition metal oxide according to claim 24 as a cathode active material. 5 [Claim 271 A lithiu111 secondary battery co~nprising the cathode according to [Claim28] A battery ~llodule co~nprising the lithiunl secondary battery according to claim 27 as a unit cell. [Claim 291 A battery pack conlprising the battery module according to claim 28. ' 10 [Claim 301 A device conlprising the battery pack according to clain129 [Claim 311 The de~rice according to claim 30, \vherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in 1q"orid electric vehicle or a power storage system. Dated this December 02,2014