Three-dimensional porous SnO2@NC framework for excellent energy conversion and storage

Abstract SnO2-based materials are deemed to be attractive electrodes for lithium/sodium ion batteries (LIBs and SIBs) and electrocatalytic CO2 reduction reaction (CRR) because of high energy density and large abundance. However, the practical application of the SnO2-based materials is prevented by low electrical conductivity and large volume change. Herein, we construct a three-dimensional (3D) porous network with SnO2 nanoparticles into N-doped carbon (namely P–SnO2@NC) synthesized by freeze drying followed by a pyrolyzation process. In the composite, the 3D hierarchical framework can facilitate the ion penetration and gas diffusion. In addition, the NC network can optimize the conductivity of the material and suppress the electrode material to fall off from the electrode. Therefore, the electrode delivers excellent electrochemical properties with high capacities of 510 mA h g−1 after 1000 cycles for LIBs and 497 mA h g−1 after 500 cycles for SIBs. Furthermore, the electrode shows high selectivity for CRR with a large coulombic efficiency (CE) of 52.7% for HCOOH at 0.6 V.