Abstract:

Lithium-ion batteries (LIBs) have been widely applied as common energy storage devices owing to their high energy and power densities, low cost, environmental friendliness, etc. The demand for developing nongraphite-based anode materials to improve battery performance is increasingly urgent. CuMoO₄ is a potential anodic material owing to its high theoretical specific capacity and low reduction potential. To address the problems of poor electrical conductivity and irreversible structural pulverization when CuMoO₄ is used as an anodic material, micro-nanostructured C/TiO₂/CuMoO₄ fibrous composite was fabricated using natural cotton fibers as the structural scaffold and C source, showing excellent electrochemical performance. The cotton fibers were first pretreated with H₂SO₄ and NaOH to increase the specific surface area, and thereafter, ultrathin TiO₂ layers were deposited on the fiber surfaces using a sol-gel method. The CuMoO₄ layers were further deposited via the layer-by-layer (LbL) self-assembly technique. The micro-nanostructure C/TiO₂/CuMoO₄ fibrous composite was obtained via calcination at 500 ℃ in an Ar atmosphere for 6 h. When applied as an anodic material for LIBs, the composite with 22.8% CuMoO₄ delivered initial discharge and charge capacities of 1212 mAh/g and 675 mAh/g, respectively, with a coulomb efficiency of 55.7%; after 200 charge-discharge cycles at 100 mA/g, the specific capacity was 403 mAh/g with a capacity retention of 59.7%, showing good cycle and rate performances. The conductivity and structural stability of the composite are improved owing to its micro-nanostructure, enhancing electrochemical performances.

Key words: lithium-ion batteries, micro-nanostructure, anodic material, copper molybdate, electrochemical performance