Overcoming the interfacial challenges of Ni-rich layered oxide cathodes for all-solid-state batteries through an ultrathin and amorphous Al2O3 coating†
Abstract
The utilization of Ni-rich layered LiNixCoyMn1−x−yO2 (NCM, x > 0.6) cathodes in all-solid-state batteries (ASSBs) holds great promise due to their high practical capacities. However, these cathodes suffer from a rapid capacity degradation due to unwanted interface side reactions with solid electrolyte. To mitigate this issue, an ultrathin (∼0.9 nm) and amorphous Al2O3 coating layer is applied to the Ni-rich NCM cathodes using atomic layer deposition (ALD). Remarkably, this nanoscale coating leads to minimal changes in the initial capacity while significantly improving the cycle retention. Through a variety of analytical techniques, we demonstrate that the Al2O3-coated NCM cathode exhibits high cycle stability by reducing the formation of insulating by-products on the surface and suppressing the irreversible phase transition during cycling. This work demonstrates the potential of employing a thin oxide coating to address the key degradation factors in Ni-rich NCM cathodes, advancing the prospects for future ASSBs.