Liquid‐Phase Preparation of Low‐Tortuosity Composite Cathode for High Active Material Content All‐Solid‐State Lithium Batteries

Abstract The all‐solid‐state lithium batteries (ASSLBs) stand as a promising candidate for the next generation of high‐energy‐density batteries with superior safety. Nevertheless, achieving high energy density in ASSLBs necessitates the simultaneous realization of high active material content and loading, posing a significant challenge in ensuring effective Li‐ion conduction within the cathode. Notably, the inhomogeneous distribution of cathode particles causes high porosity and tortuosity within the composite cathodes, thereby adversely impacting the electrochemical performance of the battery. Herein, an in situ liquid‐phase method for the fabrication of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) composite cathode is proposed. This strategy ensures the generation of uniformly distributed and densely packed composite cathode, establishing a well‐networked conduction path that ensures exceptional electronic and ionic conductivity. ASSLBs utilizing LP‐cathode exhibit outstanding electrochemical performance. It delivers a high capacity of 233.3 mAh g −1 at 0.05 C with superior rate capability and remarkable long‐term cycling stability. Moreover, ASSLBs manifest exceptional electrochemical performance, even at a high cathode active material content of 80%. This underscores the efficacy of the liquid‐phase method in constructing low‐tortuosity electrodes and accelerating charge transport kinetics, thereby enhancing the overall performance of ASSLBs. This approach holds promise for addressing the challenges associated with achieving high energy density and facilitating the development of ASSLBs.