The LiMn2O4 spinel was prepared by wet method using Li2CO3, Mn(CH3COO)2·4H2O and CO2 as raw materials. The products were measured by TG/DTA, XRD, IR. The results Showed that the sample calcined at 800℃for 10h was well crystallized monophase product. The contents of Mn?and Mn?of LiMn2O4 spinel were determined simultaneously by spectrophotometric analysis with pyrophosphoric acid.
In this paper, we report a new kind of moist chemical method for preparing LiNiVO 4 which can be used to prepare lithium ion battery for the cathode active materials with a very high battery voltage(48 V vs. Li). Li 2CO 3, NiCO 3 and NH 4VO 3 were used as row materials, and H 2C 2O 4 saturated solution was used both as a precipitate agent and as a complex agent. The precursor gel composed of (NH 4) 2(VO) 2(C 2O 4) 4·6H 2O, NiC 2O 4·2H 2O and Li 2C 2O 4 can be obtained, and after sintering the dry gel we got the products. The results of XRD show that the product sintered at 400 ℃ for 2 h exists in a cubic crystal, single phase, inverse LiNiVO 4 and the average sizes (by Scherrer formula ) were 40—50 nm(400 ℃, 2 h ) and 65—70 nm(700 ℃, 2 h) , respectively, a=0.822 3(1) nm. The TG and DTA curves implied that the dry gel underwent water loss, decompositions of oxalates and complex oxalate, the solid state reactions finished at 377 ℃. The results of XPS proved that the valence in LiNiVO 4 would be Li+,V 5+ , Ni 2+ (in the main), respectively. From ICP analysis we also knew that the sample corresponded basically to stoichiometry LiNiVO 4 .
LiNiO2 was prepared by reaction of stoichiometric amounts of thoroughly mixed LiOH· H2O and preoxidation nanometer scale Ni3O2（OH）4 powders in O2 at the temperature of 700℃ for 6h. The products were tested by XRD, XPS, SEM and electrochemistry methods. It was shown that product was LiNiO2 single phase, and the valence of nickel was + 3; the average size of it was 40nm; its initial charge specific capacity is 168mAh· g- 1 and the coulomb efficiency is 90% ; the second charge specific capacity is 160mAh· g- 1 and the coulomb efficiency is 96% .
