Abstract：A method for the analysis of average valence of transition-metalin LizNi1-x-yCoxMnyO2 cathode material of lithium ion battery has been discussed. After the samples were dissolved in hydrochloric acid medium, under the condition of pH 9-10, the total content oftransition-metalwas titrated with EDTA standard solution using murexide as indicator. The relative standard deviation of the method were between 0.06%-0.20%. In addition, the total transition-metal amount in LizNi1-x-yCoxMnyO2 samples was also determined with indirect sodium oxalate reduction titrimetry, that is, the samples in dilute sulfuric acid were reduced by quantitative sodium oxalate, and then the remaining sodium oxalate was titrated by potassium permanganate standard solution for measuring the content of the transition-metal amount in sample, and relative standard deviation of the results were between 0.17%-0.50%. The above two methods were combined to calculate the average valence of transition-metal in LizNi1-x-yCoxMnyO2, and the calculated results was accordant with the practical situation with relative standard deviation of 0.07%-0.55%.
［1］ Randolph A L, Marcus J P, Esther S T, et al. A study of the overcharge reaction of lithium-ion batteries［J］.J Power Sources, 2001, (97-98):681-683.
［2］ Tobishima S, Takei K, Sakurai Y, et al. Lithium ion cell safety［J］.J Power Sources, 2000, 90(2):188-195.
［3］ Eriksson T A, Doeff M M. A study of layered lithium manganese oxide cathode materials［J］.J Power Sources, 2003, (119-121):145-149.
［5］ Macneil D D, Lu Z H, Dahn J R. Structure and Electrochemistry of Li［NixCo1-2xMnx］O2 (0≤x≤1/2) ［J］.J Electrochem Soc, 2002, 149(10):A1332-A1336.
［6］ Lu Z H, Macneil D D, Dahn J R. Layered Cathode Materials Li［NixLi(1/3-2x/3)Mn(2/3-x/3)］O2 for Lithium-Ion Batteries ［J］.Electrochem Solid State Letters,2001, 4(11): A191-A194.
［7］ Koyama Y, Tanaka I, Ohzuku T, et al. Crystal and electronic structures of superstructural Li1-x［Co1/3Ni1/3Mn1/3］O2 (0≤x≤1)［J］.J Power Sources, 2003, (119/121):644-648.
［10］ Hollmark H M, Duda L, Dahbi M, et al. Resonant soft X-ray emission spectroscopy and X-ray absorption spectroscopy on the cathode material LiNi0.65Co0.25Mn0.1O2［J］.Journal of The Electrochemical Society, 2010,157(8) :A962-A966.
［11］ 常照荣，李华吉，汤宏伟，等.钴在高价态氧化物中平均价态的测定［J］. 电源技术(Chinese Journal of Power Sources)，2009,(1):53-54.
