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.