A case study on fibrous porous SnO2 anode for robust, high-capacity lithium-ion batteries

Abstract

Transition metal oxides have attracted considerable interest as promising anode materials for lithium-ion batteries (LIBs) due to their high energy densities. It is necessary, however, to resolve the foremost issue for them in terms of practical applications, relating to the large volume changes during cell operation. Herein, we report a SnO2 anode with a hierarchical fibrous porous architecture which was fabricated by electrospinning the Sn-precursor with poly(vinylpyrrolidone) and subsequent temperature-dependent pyrolysis processes, resulting in the distinctive morphology, featuring hierarchical fibrous porous structures on the microscale with numerous primary constituent nanoparticles. The porous fibres are composed of uniform polycrystalline nanoparticles (approximately 10–50nm in size) and abundant voids in close proximity to the constituent nanoparticles. By comparing with an anode containing commercial SnO2 nanopowder (with a size of <100nm), we found that the porous fibrous SnO2 anode featured superior rate capability, long-term cycling stability, and dimensional stability, which was attributed to the distinctive structural characteristics, which offered enhanced kinetics towards electrochemical reactions with lithium ions and space for alleviating the huge volume expansion during charging/discharging. These findings would pave the way for practical applications in LIBs with high capacity and long cycle life of transition metal oxide anodes that suffer from significant volume changes during cycling.