A Tetrathiafulvalene-based Bimetal–Organic Framework for a Hybrid Lithium-Ion Capacitor: The Role of Bimetallic Centers in Charge Storage and Stability

Abstract

Metal–organic frameworks (MOFs) have been found to be promising electrode materials for hybrid lithium-ion capacitors (HLICs) but face challenges due to their low capacity and cycling instability. Here, the first tetrathiafulvalene (TTF)-based bimetallic TTFTB-MnCo-MOF 1 was directly used as the electrode material for lithium-ion batteries, which presents enhanced performance compared with the isomorphic monometallic electrodes. Comprehensive characterizations reveal that Mn(II) in 1 is beneficial to the cycling stability and Co(II) contributes to the high specific capacity. The 1||NMC 622 full cell presents a capacity of 154.9 mAh g–1 at 100 mA g–1 in the 200th cycle. 1||AC HLIC displays a high specific energy of 141.4 Wh kg–1 at a specific power of 0.25 kW kg–1 and stable cycling performance. The remarkable performance, long-term cycling stability, and low self-discharge rate of the device are greater than those of most reported HLICs.