Molybdenum dioxide supported carbon nanotubes@carbon constructs disordered nanocluster particles as anodes for lithium-ion capacitors with long-term cycling stability

Abstract

As an emerging energy storage device, lithium-ion capacitors (LIC) can provide high-energy and power density and have received extensive attention from researchers. This paper proposes a new strategy for the synthesis of disordered CNT@C@MoO2 nanocluster particles by a two-step hydrothermal combined sintering method. Here, glucose is carbonized to form a carbon protective layer and Mo–O–C bonds are formed in the composite material, thereby suppressing the large volume expansion of MoO2 during the cycle. Moreover, the introduction of CNT@C and the presence of oxygen vacancies not only improve the conductivity of the entire electrode, but also the electrode–electrolyte contact area is accelerated, more active sites are provided, and the Li+ diffusion path is shortened. As a result, the designed multi-dimensional nanocluster carbon composite structure effectively improves the lithium storage performance of MoO2. The composite material still has a high specific capacity of 381 mAh g−1 after being cycled for 300 cycles at 0.1 A g−1, and a capacity of 148.4 mAh g−1 for 1000 cycles at 1.0 A g−1. At the same time, the calculation of cyclic voltammetry curve and capacitance contribution shows that the charge energy storage mechanism is the conversion reaction type dominated by diffusion. Then the constructed CNT@C@MoO2//AC LIC has high-energy (48.29 Wh kg−1) and power density (3600 W kg−1) and good cycling stability (82.26%@6000 [email protected] A g-1). This research work opened up a new way for the design of carbon-coated metal oxide high-performance lithium-ion capacitor anode materials.