Porous Core-Shell Tin-Based Carbon Nanofiber Networks as Free-Standing Anodes toward Advanced Lithium-Ion Batteries

Abstract Tin-based composites represent appealing anode alternatives for high-energy lithium-ion batteries because of their ultrahigh specific capacity, abundant reserves, and eco-friendly characteristics. However, their severe volume variation, electrode pulverization, and structural collapse during cycling limit their commercial applications. Herein, a free-standing core-shell porous tin-based carbon nanofiber anode was fabricated through coaxial electrospinning and subsequent high-temperature carbonization. The outer carbon shell provided further protection to stabilize the internal tin-based active cores. Meanwhile, its porous structure enabled adequate electrolyte infiltration and favorable electrode-electrolyte interfacial contact and effectively mitigated the drastic volume variation of tin-based active substances during charge/discharge cycling. Benefiting from such structural advantages, the lithium storage capability of the fabricated anode was significantly enhanced. Specifically, the optimized electrode delivered a reversible discharge capacity of 643.17 mAh/g with a capacity retention of 89.97% after 100 cycles at 500 mA/g. Moreover, it still retained a discharge specific capacity of 288.05 mAh/g at an elevated current density of 2000 mA/g, demonstrating its good rate capability.