Tetracyanoquinodimethane doped copper-organic framework electrode with excellent electrochemical performance for energy storage applications

Abstract Metal-organic frameworks (MOFs) are emerging as potential electrode materials for next-generation energy storage devices. Cu3(BTC)2 (BTC = benzene tricarboxylate), also known as HKUST-1, is one of the most widely studied MOFs. In the present work, TCNQ (tetracyanoquinodimethane) doped HKUST-1, has been demonstrated as an efficient energy storage electrode material. The infiltration of TCNQ in HKUST-1 has resulted in the synthesis of a high surface area electrode material with significant electrical conductivity. TCNQ@HKUST-1 based electrode has delivered a high specific capacity of 208.8 mAh/g (751 C/g) at a current density of 2 A/g. An all-solid-state symmetrical device has been assembled using a polymer gel electrolyte, which has delivered energy and power densities of 70.5 Wh/kg and 0.83 kW/kg, respectively. Also, the device showed a maximum energy efficiency of 58.6% along with a long cycle life of 96% over 5000 successive charging-discharging cycles. The present system has yielded superior energy storage performance than most of the earlier reported MOF based electrodes.