Gradient Design with Low‐tortuosity Overcoming Kinetic Limitations in High‐Loading Solid‐State Cathodes

The extensive commercialization of practical solid‐state batteries (SSBs) necessitates the development of high‐loading solid‐state cathodes with fast charging capability. However, electrochemical kinetics are severely delayed in thick cathodes due to tortuous ion transport pathways and slow solid‐solid ion diffusion, which limit the achievable capacity of SSBs at high current densities. In this work, we propose a conductivity gradient cathode with low‐tortuosity to enable facile ion transport and counterbalance ion concentration gradient, thereby overcoming the kinetic limitations and achieving fast charging capabilities in thick cathodes. The LiNi0.8Co0.1Mn0.1O2 cathodes deliver a room‐temperature (RT) capacities of 147 and 110 mAh g‐1 at 5 C and 10 C, respectively, and meanwhile achieve a RT areal capacity of 3.3 mAh cm‐² at 3 C, enabling SSBs simultaneously high energy and power densities. The universality of this strategy is demonstrated in LiFePO4 cathodes, providing a novel solution for fast charging and large‐scale application of high‐loading SSBs.