CoS Nanosheets Coated with Dopamine-Derived Carbon Standing on Carbon Fiber Cloth as Binder-Free Anode for Li-ion Batteries

Cobalt sulphides attract much attention as anode materials for Li-ion batteries (LIBs). However, its poor conduc-tivity, low initial column efficiency and large volume changes during cycling have hindered its further develop-ment. Herein, novel interlaced CoS nanosheets were firstly prepared on Carbon Fiber Cloth (CFC) by two hydrothermal reactions followed with carbon coating via carbonizing dopamine (CoS NS@C/CFC). As a freestanding anode, the nanosheet structure of CoS not only accommodates the volume variation, but also provides a large interface area to proceed the charge transfer reaction. In addition, CFC works as both a three-dimensional skeleton and an active substance which can further improve the areal capacity of the resulting electrode. Further-more, the coated carbon combined with the CFC work as a 3D conductive network to facilitate the electron con-duction. The obtained CoS NS@C/CFC, and the contrast sample prepared with the same procedure but without carbon coating (CoS NS/CFC), are characterized with XRD, SEM, TEM, XPS and electrochemical measurements. The results show that the CoS NS@C/CFC possesses much improved electrochemical performance due to the synergistic effect of nanosheet CoS, the coated carbon and the CFC substrate, exhibiting high initial columbic efficiency (~87%), high areal capacity (2.5 at 0.15 mA cm⁻²), excellent rate performance (1.6 at 2.73 mA cm⁻²) and improved cycle stability (87.5% capacity retention after 300 cycles). This work may provide a new route to explore freestanding anodes with high areal specific capacity for LIBs.