Construction of K-doped mixed-phase TiO2 nanowires@MoS2 nanosheets core-shell structure for researching on supercapacitors

Abstract

To enhance the specific capacitance of titanium-based supercapacitor, a novel binder-free titanium supported electrode material is first assembled with K-doped mixed-phase (anatase and rutile) TiO2 nanowires coated by MoS2 nanosheets (K-TNW@MNs). The K-TNW@MNs core-shell structure is prepared by chitosan-assisted hydrothermal reaction. The soft template of chitosan is chosen to grow MNs uniformly on K-TNW and reduce the agglomeration of MNs. K-TNW backbone structure provides a large surface area for attaching and anchoring the MoS2 nanosheets. As a result, The K-TNW@MNs exhibits a high specific capacitance of 123.53 mF cm−2 at 0.4 mA cm−2, desirable rate capability, and outstanding cycling stability of 84.49% capacitance retention over 6000 cycles. A novel all-solid-state symmetrical supercapacitor assembled with two pieces of K-TNW@MNs electrodes and KCl/polyvinyl alcohol gel electrolyte exhibits a good capacitance retention rate of 78.44% after 6000 cycles. The researches offer a novel strategy to reduce the agglomeration of MoS2 nanosheets on TiO2 nanowires by chitosan-assisted.