Electrospun SnSb crystalline nanoparticles inside porous carbon fibers as a high stability and rate capability anode for rechargeable batteries

In an electrochemical alloying reaction, the electroactive particles become mechanically unstable owing to large volume changes occurring as a result of high amounts of lithium intake. This is detrimental for long-term battery performance. Herein, a novel synthesis approach to minimize such mechanical instabilities in tin particles is presented. An optimal one-dimensional assembly of crystalline single-phase tin–antimony (SnSb) alloy nanoparticles inside porous carbon fibers (abbreviated SnSb–C) is synthesized for the first time by using the electrospinning technique (employing non-oxide precursors) in combination with a sintering protocol. The ability of antimony to alloy independently with lithium is beneficial as it buffers the unfavorable volume changes occurring during successive alloying/dealloying cycles in Sn. The SnSb–C assembly provides nontortuous (tortuosity coefficient, τ = 1) fast conducting pathways for both electrons and ions. The presence of carbon in SnSb–C completely nullifies the conventional requirement of other carbon forms during cell electrode assembly. The SnSb–C exhibited remarkably high electrochemical lithium stability and high specific capacities over a wide range of currents (0.2–5 A g⁻¹). In addition to lithium-ion batteries, it is envisaged that SnSb–C also has potential as a noncarbonaceous anode for other battery chemistries, such as sodium-ion batteries