Structural design and fabrication of metal vanadate hydrates for wearable electronic applications

Abstract

The structural design of electroactive materials including rich profits of high capacitance/capacity and exalted durability is of considerable importance in the development of high-performance wearable energy storage technologies. Herein, a simple and single-step hydrothermal approach is demonstrated to design hierarchical feathers-like microsheet arrays for asymmetric supercapacitors (ASCs) with stable cycling performance. The preparation is carried out at low temperatures without any annealing process, and the as-designed nickel/cobalt vanadate hydrates supported on conductive carbon cloth textile are endowed with the unique architecture of feathers-like microsheets, which allows for the effective contact of active materials, rapid ion diffusion, easy electrolyte penetration, and fast electron transfer. Considering these merits in amalgamation, the Ni0.33Co0.67 vanadate hydrate active material shows a superior areal/specific capacity value of 373.9 µAh cm−2/140 mAh g−1 with outstanding cycling performance (100,000 cycles) than those in the design of mono NiV and CoV hydrates as well as the other fabricated electrode (Ni:Co ratio) materials. Furthermore, the Ni0.33Co0.67 vanadate hydrate active material, when employed as a positive electrode for ASCs, demonstrates excellent electrochemical performance. The assembled ASC exhibits high energy and power density values of 0.19 mWh cm−2 and 2.04 mW cm−2, respectively along with remarkable cycling retention of 82.2% after the completion of 100,000 cycles. Also, the as-assembled device was tested by powering different wearable electronics. This work creates a new pathway for the fabrication of single-step Ni-Co vanadate hydrates for durable electrochemical energy storage applications.