Correlation between local strain and cycle-life performance of AlPO4-coated LiCoO2 cathodes

AlPO4-coated LiCoO2 cathodes display improved cycle-life performance compared with bare LiCoO2. This is attributed to suppression of cobalt dissolution from the cathodes by the AlPO4-nanoparticle coating. Dissolution of cobalt during cycling with a charge cut-off voltage of 4.6 V leads to structural degradation, and induces a non-uniform distribution of local strain in the cathodes. The strain in coated samples is significantly reduced after 50 cycles, and is correlated with the enhanced cycle-life performance.