Biomass-derived, 3D interconnected N-doped carbon foam as a host matrix for Li/Na/K-selenium batteries

Rechargeable alkali metal-Se batteries have attracted a lot of attention due to their high capacity and low cost. However, the shuttle effect and volume change during charge/discharge are the main obstacles for further development of high-performance alkali-Se rechargeable batteries. In order to solve these issues, herein a biomass-derived 3D interconnected foam-like N-doped porous carbon (FNDPC) is synthesized as a Se-container for metal-Se batteries. In this [email protected] structure, stable porous carbon hosts can serve as chambers for Se reacting with Li+, Na+ or K+. As expected, the [email protected] electrode exhibits an ultrahigh rate performance and excellent cycling stability during the reversible storage of alkali metal ions. For Na-Se batteries, the high specific capacity of 354.9 mAh g−1 is achieved even at a high current density of 20 A g−1 and there is 90.7% capacity retention after 500 cycles at 2.0 A g−1. For Li-Se batteries, [email protected] can offer an impressive rate capability with specific capacities of 653.1 mAh g−1 at 0.1 A g−1 and 350.4 mAh g−1 at 20 A g−1. In contrast, the performance of [email protected] in K-Se batteries is relatively lower than that in Li-Se and Na-Se batteries. Moreover, different energy-storage mechanisms for three types of ions are also revealed by cycling voltammetry (CV). Therefore, FNDPC is considered to be a promising carbon host for alkali-Se batteries, and our reported method provides possibilities for mass production of alkali-Se battery through the cheap raw materials.