摘要
Reasona ble structural frame modification and further optimization design of traditional substrates are favorable schemes to break through the current insufficient energy density of electrode materials for supercapacitors. Transition metal chalcogenides are being investigated as electrode materials for supercapacitors due to their exceptional energy storage capacity. However, single transition metal selenides, transition metal sulfides, or traditional transition metal selenides all have the problems of insufficient conductivity and structural collapse caused by charging and discharging, which limit their path to marketization. In this work, an isomorphic cobalt‑manganese‑selenium sulfide supported by MXene quantum dots (MQDs) based on ZIF was developed using a two-step hydrothermal method to address the energy storage disadvantages of chalcogenides. Thanks to the unique isomorphic skeleton design (enhancing the synergistic effect of selenium and sulfur) and the advantages of MQDs (short-range ion diffusion path) wrapped inside and outside selenium sulfide, MQDS@Mn 0.6 Co 0.4 Se/Mn 0.77 Co 0.23 S composite as supercapacitor electrode broke through the voltage window (0.5 V) of transition metals in alkaline environment, and its charge-discharge window was as high as 0.55 V when the specific capacitance was 1 A g −1 . The assembled asymmetric supercapacitor (ASC) can operate within a large voltage window of 1.6 V. When the power density reaches 817.52 W kg −1 , the energy density is as high as 83.91 Wh kg −1 . At 1.6 V (0.1 V above traditional), capacitance retention drops by only 13.09 % over 10,000 cycles. This study proposes a novel approach to the rational design of transition metal chalcogenides and the transformation of MXene substrates, resulting in electrode materials with prolonged charge-discharge times and a wide voltage window. This discovery provides a new avenue for developing advanced supercapacitor electrodes.
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