Post-Test Analysis of Battery Materials: Another Part of the Question

Post-test analyses of cells consisting of a layered-layered cathode, a graphite anode and an organic carbonate-based electrolyte were performed. Many changes in the cell components were visible. Gas analysis revealed possible evidence of oxygen evolution from cathode and electrolyte degradation, including likely reaction products between electrolyte solvents and salt or binder. The anode surface was highly inhomogeneous and was comprised of a surface film of varying thickness, white precipitates, and dendritic growth of metallic Li and/or deliquescent salts. Manganese was incorporated into the anode and P, C, and O were preferentially incorporated into some areas of the anode surface. Analysis of the composition of the SEI layer shows that, unsurprisingly, it was complex.