Ionic liquid assisted electrospinning synthesis for ultra-uniform Sn@ mesoporous carbon nanofibers as a flexible self-standing anode for lithium ion batteries

Highlights: : • Uniform electrospun solution is available through ionic liquid modified SnO₂ particles. • Mesoporous carbon fibers structure is constructed by introducing ionic liquid to electrospinning. • The Sn@MCNF-IL anode presented higher capacity, long cycling life and superior rate performance. -- Abstract: The long-cycle-life and high-capacity Sn@ Mesoporous Carbon Nanofibers (Sn@MCNFs-IL) self-standing anode was prepared by ionic liquid assisted electrospinning and pyrolysis strategy. Ionic liquid (AminCl) modifies the interface between the active particles and the electrospinning solutions, affecting electrospinning and pyrolysis process. The structure of ultra-uniform Sn encapsulated in porous carbon nanofibers resolves severe aggregation of Sn nanoparticles in carbon nanofibers, thus releasing stress form volume expansion of Sn and increasing storage lithium ions surface area of the Sn. The ultra-uniform Sn@MCNF-IL anode exhibited high capacity of 750 mA h g⁻¹ at 0.5 A g⁻¹ (comparing with Sn@CNF anode, improved 22%) with excellent Coulombic efficiency (89% at 1st cycle) and rate performance (300, 200 mA h g⁻¹ at 4.0 and 10.0 A g⁻¹). Remarkably, the cycling capability of the Sn@MCNF-IL anode (504 mA h g⁻¹, 800 cycles at 0.5 A g⁻¹) is superior to the cycling performance of Sn@CNF. The ionic liquid assisted strategy hopefully provides an advanced strategy in construction of excellent self-standing anode and the Sn@MCNFs-IL shows great promise as a candidate anode for superior performance flexible lithium-ion batteries.