High-rate and long-life Ni-rich oxide cathode under high mass loading for sulfide-based all-solid-state lithium batteries

Abstract

The interface side reaction and mechanical failure are the main factors affecting electrochemical performances of Ni-rich oxide cathode for sulfide-based all-solid-state lithium batteries (ASSLBs). It is believed that the interface side reaction is mainly caused by the high nickel content and residual lithium compounds on the surface, and the mechanical failure is mainly caused by severe volume change during cycling. In view of this, core-shelled Ni-rich Li(Ni0.9Mn0.05Co0.05)0.8Co0.2O2 is constructed and further modified with Al source. In this strategy, the core-shell structure design of Ni-rich oxide material can decrease the surface nickel content and reduce the volume change, and the surface modification process of core-shelled Ni-rich oxide material with aluminum isopropoxide can generate Al-modifying layer (Al2O3 and LiAlO2 layer), which will not only remove the lithium compounds but also form the coating layer. Under high mass loading of 36.94 mg cm−2, Al-modified Li(Ni0.9Mn0.05Co0.05)0.8Co0.2O2 (CS-NCM@Al) cathode displays the discharge capacity of 158.6 mAh g−1 at 0.2 C with high initial coulombic efficiency of 88.3%. More significantly, it shows a significant capacity retention of 96.3% after 500 cycles at 1 C (7.39 mA cm−2). This work opens up a new avenue for meeting the future application of high energy density sulfide-based ASSLBs.