Oxidized Co-Sn nanoparticles as long-lasting anode materials for lithium-ion batteries

Herein, we present the synthesis and systematic comparison of Sn- and Co-Sn-based nanoparticles (NPs) as anode materials for lithium-ion batteries. These nanomaterials were produced via inexpensive routes combining wet chemical synthesis and dry mechanochemical methods (ball milling). We demonstrate that oxidized, nearly amorphous CoSn₂O_x NPs, in contrast to highly crystalline Sn and CoSn₂ NPs, exhibit high cycling stability over 1500 cycles, retaining a capacity of 525 mA h g^-1 (92% of the initial capacity) at a high current density of 1982 mA g^-1. Moreover, when cycled in full-cell configuration with LiCoO₂ as the cathode, such CoSn₂O_x NPs deliver an average anodic capacity of 576 mA h g^-1 over 100 cycles at a current of 500 mA g^-1, with an average discharge voltage of 3.14 V.