Cd-Doped FeSe nanoparticles embedded in N-doped carbon: a potential anode material for lithium storage

Transition metal selenides have become the focus of research in recent years, owing to their large specific capacity and fast charging/discharging speed. However, the rapid decay of the specific capacity resulting from the large volume change that occurs during cycling and the damage caused to the electrode structure, seriously impedes their practical applications. In this work, Cd-doped Fe 3 C nanoparticles embedded in nitrogen-containing carbon (Fe 3 C-Cd n /C-N) precursors were first prepared using a simple sol-gel method, and then FeSe doped with Cd loaded on nitrogen-containing carbon (FeSe-Cd n /C-N) composites were obtained using a selenization process. These composites exhibited a high conductivity and special structural durability, thus ensuring good charge transport kinetics. As expected, the FeSe-Cd n /C-N electrode displayed a high specific capacity, excellent rate performance and ultra-stable long-term cycling stability. It delivered a reversible capacity of 745 mA h g −1 for 550 cycles at a rate of 2.0C, much higher than that of the non-Cd doped FeSe/C-N (288 mA h g −1 ). More impressively, it maintained a capacity of 438.8 mA h g −1 at 5.0C during the rate capability testing, exhibiting an excellent rate performance. The results demonstrate that iron-based selenides have good prospects for further development and that cadmium doping can significantly improve the electrochemical performance of lithium ion batteries. Cd doped FeSe nanoparticles loaded on nitrogen-containing carbon (Fe 3 C-Cd n /C-N) composites were obtained and displayed a high specific capacity, excellent rate performance and ultra-stable long-term cycling stability.