Microtubular SnO 2 /V 2 O 5 Composites Derived from Cellulose Substance as Cathode Materials of Lithium‐ion Batteries

Three‐dimensional microtubular SnO 2 /V 2 O 5 composites with various SnO 2 contents (2.2, 12.1 and 25.2 wt%) were fabricated by a facile sol−gel method employing natural cellulose substance (e. g., filter paper) as template. Thin V x O y /SnO 2 gel layer was first deposited onto the surfaces of the cellulose microfibers of the filter paper through a dipping process, and then the as‐prepared V x O y /SnO 2 /cellulose composites were calcined in air to give the SnO 2 /V 2 O 5 composites. The obtained composites inherit the morphology of the initial cellulose substance on the micrometer scale and consist of intricate microtubes composed of V 2 O 5 nanorods with SnO 2 nanoparticles anchored on the surfaces. Due to the unique three‐dimensional network structure of the composites and the synergetic effect of the V 2 O 5 and SnO 2 species, the SnO 2 /V 2 O 5 composites displayed enhanced electrochemical performances when employed as cathode materials for lithium‐ion batteries. The composite with a SnO 2 loading content of 12.1 wt% retained a stable discharge capacity of 126 mAh g −1 after 150 discharge/charge cycles at a current density of 0.1 A g −1 . The three‐dimensional microtubular structure inherited from the cellulose substance improves the structural stability of the electrode materials and facilitates the diffusion of lithium ions, and the existence of SnO 2 with an appropriate loading content enhances the conductivity of the composites.