Enhanced elevated-temperature performance of Li(Ni0.8Co0.15Al0.05)O2 electrodes coated with Li2O-2B2O3 glass

Abstract

Poor capacity retention, accompanied by structure deterioration and transition metal dissolution, remains an unsolved problem for Li(Ni0.8Co0.15Al0.05)O2 at elevated temperatures. We confirm that samples coated with LBO glass show suppressed structure deterioration and transition metal dissolution at elevated temperature by the variation in differential capacity and low open circuit voltage decay values, which leads to improved elevated-temperature performance. In particular, a 2wt.% LBO-glass–coated sample provides a high capacity retention of 94.2% after 100 cycles, compared with 75.3% for an uncoated specimen. In addition, the LBO glass coating, possessing a high ionic conductivity, leads to good discharge capacities at elevated temperature: 169 and 147mA h g−1 at current densities of 360 and 900mAg−1, respectively, compared with 159 and 133mA h g−1 for the uncoated sample. The LBO glass coating reduced the resistance for both surface film and charge transfer sources. In addition, the LBO-glass–coated sample possesses good thermal stability; the heat generation in the sample was reduced to 418.0Jg−1 from 565.2Jg−1 in the uncoated sample.