Unleashing the power of 3D Ti3C2Tx: A breakthrough in electrochemical energy storage

The tendency of Ti3C2Tx nanosheets to be stacked makes it challenging to immobilize the active material, thus limiting the performance of the storage device. Integrating two-dimensional Ti3C2Tx into three-dimensional (3D) structures is considered one of the important yet challenging approaches to realize ultra-high-performance supercapacitors. In this study, we report the preparation of Ti3C2Tx into a 3D network interconnection structure using the sacrificial template method, with polydopamine (PDA) serving as a coating material for encapsulation. Subsequently, the Ti3C2Tx/PDA composite is combined with NiS as an electrode material. The 3D Ti3C2Tx structure effectively hinders the stacking of Ti3C2Tx, while the –OH groups on the surface of PDA form non-covalent interactions with the functional groups of 3D Ti3C2Tx, preventing its oxidation and accelerating electron transfer. The nitrogen atom in PDA can anchor Ni-S to avoid its detachment, which leads to better electrochemical properties of the prepared composites. Ni-S/3D Ti3C2Tx@PDA as an electrode material had a high specific capacitance of 352.36 mAh/g (1 A/g). The asymmetric supercapacitor using Ni-S/3D Ti3C2Tx @PDA as the anode material achieved a high energy density of 35.5 W kg−1 at 1600 W kg−1 power density, and excellent cycling stability, possessing 98.83 % cycle retention and 84.98 % capacity efficiency at 3 A/g for 10,000 cycles. In summary, it can be seen that Ni-S/3D Ti3C2Tx @PDA materials have great potential for development in supercapacitors.