High Energy X-Ray Used to Investigate the Synthesis of  Full Concentration Gradient Cathode

Tuesday, October 13, 2015: 16:40
105-A (Phoenix Convention Center)
Y. Li (Argonne National Laboratory), R. Xu, Y. Ren (Argonne National Laboratory, Advanced Photon Source), J. Lu, H. Wu, L. Wang (Argonne National Laboratory), D. Miller, Y. K. Sun (Hanyang University), K. Amine (Argonne National Laboratory), and Z. Chen (Argonne National Laboratory)
Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but there is a concern about the highly reaction between the cathode and the non-aqueous electrolytes. To maintain high specific capacity and improve cycling performance , we have employed solid state reaction to synthesize a full concentration gradient (FCG) cathode, which has a nominal composition of LiNi0.6Mn0.2Co0.2. It is  designed to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. The solid-state reaction to form a high performance nickel-rich cathode material is a complicated multiple-step reaction.  Therefore, in situ high-energy X-ray diffraction was utilized to study the structural evolution during the solid-state synthesis of FCG cathode. We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li2CO3 and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this talk can also be utilized for the design of other nickel-rich high energy-density cathode materials.