3D multicore-shell CoSn nanoboxes encapsulated in porous carbon as anode for lithium-ion batteries

Due to its high theoretical capacity and appropriate potential platform, tin-based alloy materials are expected to be a competitive candidate for the next-generation high performance anodes of lithium-ion batteries. Nevertheless, the immense volume change during the lithium-ion insert process leads to severe disadvantages of structural damage and capacity fade, which limits its practical application. In this work, a three-dimensional (3D) multicore-shell hollow nanobox encapsulated by carbon layer is obtained via a three-step method of hydrothermal reaction, annealing and alkali etching. During the electrochemical reactions, the CoSn@void@C nanoboxes provide internal space to compensate the volumetric change upon the lithiation of Sn, while the inactive component of Co acts as chemical buffers to withstand the anisotropic expansion of nanoparticles. Owing to the above-mentioned advantages, the elaborated anode delivers an excellent capacity of 788.2 mAh/g at 100 mA/g after 100 cycles and considerable capacity retention of 519.2 mAh/g even at a high current density of 1 A/g after 300 cycles. The superior stability and high performance indicate its capability as promising anodes for lithium-ion batteries. Three-dimensional multicore-shell hollow CoSn@void@C nanoboxes have been successfully fabricated via a hydrothermal strategy, which exhibits the enhanced capacity and robust electrochemical stability.