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.