Synthesis And Electrochemical Performance Of New Cathode Materials Li_x/3+1Ni_1/2-x/2-y/2Mn_x/6+1/2-y/2Cr_yO₂

With the development of lithium ion battery, one of the challenges for improving theperformance of lithium ion batteries is the development of suitable cathode materials tomeet increasingly demanding requirements for energy storage. Li [Ni, Co, Mn]O₂compound has been considered as a promising candidate of next-generation cathodematerials for the rechargeable lithium ion batteries due to its large capacity, stable structureand lower cost. Cobalt is less available, and thus more costly, even radioactive. So we usechromium to replace cobalt due to its lower cost and less expensive. Furthermore, becausethe possible valence states of chromium are+3,+4,+6, so, it can help cathode materials toaccept and release more lithium ions repeatedly and improve the capacity of lithium ionbattery.In this paper, a simple but novel route was firstly proposed for preparing Li [Ni, Mn,Cr] O₂cathode materials. Technological conditions of this synthesis method wereinvestigated systematically and optimized. The materials were characterized by TG/DTA、XRD、SEM and galvanostatic charge-discharge test.The multiple doping Li-ion battery cathode materials Li_x/3+1Ni_1/2-x/2-y/2Mn_x/6+1/2-y/2Cr_yO₂（0≤x≤1,0≤y<0.4, x+y≤1） were synthesis by hydrothermal and solid state reaction,to make this simpler. The materials were characterized by XRD, SEM, XPS andgalvanostatic charge-discharge test. The results show that the prepared samples are highcrystallinity and uniform size distribution. At room temperature, the test was carried out ina voltage range from2.0to5.0V at0.2C rate，the sample Li1.1833Ni0.2Mn0.5667Cr0.05O₂hasthe best electrochemical performance and the initial charge and discharge capacity is153.5mAh/g and213.8mAh/g, respectively. In addition, the sample Li_1.2Ni_0.2Mn_0.6O₂shows excellent cycle stability with little orno capacity loss after30cycles.