Constructing carbon nanotubes/SnO2/void@reduced graphene oxide film as a self-standing anode for ultra-stable sodium half/full battery

We report a novel carbon nanotubes/SnO2/void@reduced graphene oxide (CNTs/SnO2/void@rGO) film, which was prepared by a simple hydrothermal and annealing process and used as a self-standing anode for ultra-stable half/full sodium battery (SIB). Functionally, many voids are intelligently designed in CNTs/SnO2/void@rGO film to effectively shorten the electron/Na+ ion diffusion path. The highly conductive CNTs and rGO form a doublelayer electron transmission channel, which can simultaneously accelerate the reaction kinetics and alleviate the volume expansion of SnO2. Besides, CNTs/SnO2/void@rGO film can be directly used as a self-standing anode to avoid the impact of non-conductive adhesives on the electrochemical performance of the SIBs. Benefit by this unique design, the CNT/SnO2/void@rGO film as sodium half-cell anode offers a high reversible capacity of 416.5 mA h g-1 at 0.1 A/g. More importantly, a sodium-ion full-cell was assembled by using CNTs/SnO2/ void@rGO film as anode and Na3V2(PO4)3 as cathode, which successfully lit many LEDs. This work provides a novel design idea for the realization of ultra-stable half/full sodium batteries.