Construction of Multifunctional Conductive Carbon-Based Cathode Additives for Boosting Li6PS5Cl-Based All-Solid-State Lithium Batteries

Abstract

The electrochemical performance of all-solid-state lithium batteries (ASSLBs) can be prominently enhanced by minimizing the detrimental degradation of solid electrolytes through their undesirable side reactions with the conductive carbon additives (CCAs) inside the composite cathodes. Herein, the well-defined Mo3Ni3N nanosheets embedded onto the N-doped porous carbons (NPCs) substrate are successfully synthesized (Mo-Ni@NPCs) as CCAs inside LiCoO2 for Li6PSC5Cl (LPSCl)-based ASSLBs. This nano-composite not only makes it difficult for hydroxide groups (–OH) to survive on the surface but also allows the in situ surface reconstruction to generate the ultra-stable MoS2-Mo3Ni3N heterostructures after the initial cycling stage. These can effectively prevent the occurrence of OH-induced LPSC decomposition reaction from producing harmful insulating sulfates, as well as simultaneously constructing the highly-efficient electrons/ions dual-migration pathways at the cathode interfaces to facilitate the improvement of both electrons and Li+ ions conductivities in ASSLBs. With this approach, fine-tuned Mo-Ni@NPCs can deliver extremely outstanding performance, including an ultra-high first discharge-specific capacity of 148.61 mAh g−1 (0.1C), a high Coulombic efficiency (94.01%), and a capacity retention rate after 1000 cycles still attain as high as 90.62%. This work provides a brand-new approach of “conversion-protection” strategy to overcome the drawbacks of composite cathodes interfaces instability and further promotes the commercialization of ASSLBs.