Bimetallic CoMoS Composite Anchored to Biocarbon Fibers as a High-Capacity Anode for Li-Ion Batteries

Our work reports the hydrothermal synthesis of a bimetallic composite CoMoS, followed by the addition of cellulose fibers and its subsequent carbonization under Ar atmosphere (CoMoS@C). For comparison, CoMoS was heat-treated under the same conditions and referred as bare-CoMoS. X-ray diffraction analysis indicates that CoMoS@C composite matches with the CoMoS₄ phase with additional peaks corresponding to MoO₃ and CoMoO₄ phases, which probably arise from air exposure during the carbonization process. Scanning electron microscopy images of CoMoS@C exhibit how the CoMoS material is anchored to the surface of carbonized cellulose fibers. As anode material, CoMoS@C shows a superior performance than bare-CoMoS. The CoMoS@C composite presents an initial high discharge capacity of ∼1164 mA h/g and retains a high specific discharge capacity of ∼715 mA h/g after 200 cycles at a current density of 500 mA/g compared to that of bare-CoMoS of 102 mA h/g. The high specific capacity and good cycling stability could be attributed to the synergistic effects of CoMoS and carbonized cellulose fibers. The use of biomass in the anode material represents a very easy and cost-effective way to improve the electrochemical Li-ion battery performance.