Facial design and synthesis of CoAl-LDH-doped MXene with nanosheet structure for high-performance asymmetric supercapacitors

Optimizing the performance of layered double hydroxide (LDH) electrodes by MXene is of significant importance for high-performance asymmetric supercapacitors. In this paper, CoAl-LDH nanosheet-doped s-MXene composites were prepared by a facile hydrothermal method, and two-dimensional layered microstructured CoAl-LDH/s-MXene electrode materials with excellent performance were prepared. The homogeneous growth of CoAl-LDH on s-MXene successfully hinders the agglomeration of CoAl-LDH and provides more layered channels for electron and ion transfer across the electrode material. In addition, CoAl-LDH can effectively suppress the stacking of s-MXene, which increases the electrochemical active site of the material, resulting in an increase in specific capacity. The CoAl-LDH/s-MXene electrode material has a high specific capacity of 1259.9 C g-1 at 1 A g-1, which has outstanding specific capacity and rate capability. The assembled asymmetric CoAl-LDH/s-MXene//AC supercapacitor achieves the desired energy density of 104 and 88 Wh kg-1 at 1500 and 6000 W kg-1. After 5000 laps at 10 A g-1, CoAl-LDH/s-MXene//AC has a capacitance retention rate of 86.6% and a coulomb efficiency of nearly 100%, demonstrating its splendid cycling stability. Therefore, this paper adopts a simple hydrothermal method to prepare CoAl-LDH/s-MXene active material, which provides an effective strategy for constructing supercapacitors with excellent performance.