Synthesis, in-situ TEM characterization and electrochemical behaviors of Sb₂Te₃/C nanocomposite for sodium-ion batteries

The limited resource of Li cannot satisfy the rapid development of Li-ion batteries applications. Na-ion battery is respected as a potential alternative because Na possesses the abundant storage. Sb-based anode materials are attracting more attention owing to the high capacity, but the poor cyclic property caused by the huge volume change during sodiation and desodiation is still a problem. Usually, the cyclic performance is improved by introducing inactive elements but sacrificing the capacity simultaneously. Here, we introduce Na-active Te to Sb₂Te₃/C nanocomposite where Sb₂Te₃ nanocrystals (~20 nm) embedded in the carbon matrix, via a high-energy ball-mill method. The specific capacity of Sb₂Te₃/C electrode could deliver 360 mA h g^–1 at 1 A g^–1. Moreover, its capacity retention is as high as 93% after 400 cycles. In-situ TEM analysis indicates that the stress during volume change can be released and the pulverized nanoparticles aggregation can be suppressed efficiently by the synergetic effects of carbon matrix and nanosized particles.