Flexible All-Solid-State Asymmetric Supercapacitor Based on In Situ-Grown Bimetallic Metal Sulfides/Ti3C2Tx MXene Nanocomposite on Carbon Cloth Via a Facile Hydrothermal Method

Herein we report the in situ growth of bimetallic metal sulfides (NiCo2S4 and MnCo2S4)/Ti3C2Tx MXene nanocomposite on activated carbon cloth (CC) via a simple hydrothermal method. The synergistic coupling and microporous structures of bimetallic metal sulfides/Ti3C2Tx MXene on CC exhibit better conductivity. As a result, the fabricated MnCo2S4@ Ti3C2Tx -CC and NiCo2S4@ Ti3C2Tx -CC electrodes show good areal capacitance of 274 and 206 mF/cm2 at current density of 0.6 and 0.4 mA/cm2, respectively. Further, an all-solid-state asymmetric supercapacitor device was fabricated by combining it with the AC-CC. Compared with other flexible NiCo2S4@Ti3C2Tx //AC devices, the MnCo2S4@Ti3C2Tx //AC solid-state asymmetric device exhibits maximum areal energy density of 20 μWh/cm2 and maximum areal power density of 1.24 mW/cm2 with areal capacitance of 63.30 mF/cm2. Without sacrificing rate capability, it demonstrated excellent electrochemical energy storage performance, with 80% of capacitance retention over 5000 cycles. The device also showed good mechanical and electrical stability when bent at different angles. The NiCo2S4@Ti3C2Tx // AC device shows excellent cycling stability, with 84% of capacitance retention over 5000 cycles. The present work provides a reliable and scalable approach to producing flexible electrode materials for energy storage applications.