A highly-effective nitrogen-doped porous carbon sponge electrode for advanced K-Se batteries

A rechargeable K-Se battery is emerging as an energy storage system because of its much higher specific capacity than that of the traditional alkali metal-ion batteries, but is facing some critical issues and challenges. Exploiting stable and efficient Se-based cathode materials is one of the key points for addressing the intrinsic drawbacks of this new system. Herein, we developed an effective electrode (nitrogen-doped porous carbon sponge) to serve as an advanced electrode for K-Se batteries. The novel electrode presents good multifunctional characteristics, such as efficient confinement of selenium, valid accommodation of volumetric change, stable conductive framework and promotion of fast electron/ion transportation. Accordingly, desirable electrochemical performances are achieved when the as-obtained Se/carbon composite is used as the cathode of K-Se batteries. This work, via smart and efficient electrode design, unfolds a new idea to accelerate the development of advanced K-Se batteries.