Flexible wire-shaped symmetric supercapacitors with Zn–Co layered double hydroxide nanosheets grown on Ag-coated cotton wire

Flexible wire-shaped supercapacitors have attracted wide interest due to the increasing demand for portable and wearable electronics. Due to the complex functioning atmosphere of wearable electronics, their mechanical stability and electrochemical stability under different bending states are required. In this work, the self-made Ag-coated cotton wire was adopted as the collector and zinc–cobalt layered double hydroxide nanosheets were successfully electrodeposited on this wire (Ag-CW@ZnCo-LDH) by a facile chronopotentiometry with a constant current of 0.02A. Ag-CW@ZnCo-LDH electrode displayed a high specific capacitance of 1732.4 F g⁻¹ at 1 A g⁻¹ and 61.7% of capacitance retention after 2000 cycles at 10 A g⁻¹. Flexible wire-shaped symmetric supercapacitor was fabricated by two same Ag-CW@ZnCo-LDH electrodes, which exhibited a working potential window of 1.2 V. The as-assembled WSSC showed a good electrochemical performance with specific capacitance of 16.3 F g⁻¹ and energy density of 1.33 Wh kg⁻¹ at power density of 1224 W kg⁻¹. In addition, its CV curves barely deviated at all bending angles, manifesting the outstanding mechanical stability and great potential for practical application.