Pathways toward Improved Performance of NCM523 Pouch Cell via Incorporating Low-Cost Al₂O₃ and Graphene

Improving the holistic capability for lithium-ion batteries (LIBs) using an efficient and convenient approach with a minimum cost increase remains one of the most urgent and challenging issues for LIB industrialization. This work delivers such an approach via an extremely simple path. Low-cost reagents of Al2O3 and graphene sheets (Gs) are used as additives for LiNi05Co0.2Mn0.3O2 (NCM523)∥graphite pouch cells. Interestingly, with very low concentrations (only 1.0 and 0.5 wt % for Al2O3 and graphene), additives enable dramatically improved LIB performance, from cyclic stability, energy density, to thermal safety. The assembled cell of NCM523-Al2O3-Gs∥graphite delivered a capacity retention of 76.9% at 3.0 C after 400 cycles (cf. only 73.6% for a pure NCM cell). More significantly, the heat generation during the discharging under 3.0 C and safety tests are both superior to those of a pure NCM cell. It is proven that the excellent LIB performance benefits from the co-effect of additives of Al2O3 and Gs, which not only inhibit the structure failure and enhance conductance of materials but also optimize the interface compatibility of an electrolyte and slow down the thermal runaway possibility, especially at high rates and elevated temperatures. This work provides a powerful and convenient solution for the commercial achievement of high-performance LIBs.