Enhancing energy storage capacity of B³⁺-intercalated Ti₃C₂T_x by combining its three-dimensional network structure with hollow carbon nanospheres

Ti₃C₂T_x shows potential as an electrode material of supercapacitors due to its unique layered structures for ion diffusion as well as excellent chemical/physical properties. However, the layer stacking and the insufficient conductivity due to the terminated surface groups have limited this application essentially. In the present study, a three-dimensional B³⁺ ion-intercalated Ti₃C₂T_x network (B-Ti₃C₂T_x) was combined with hollow carbon nanospheres (HCNS), which improved the electric transport performance of Ti₃C₂T_x by reducing the surface functional groups and hindering the restacking of Ti₃C₂T_x nanosheets effectively. Thus, a new set of 3D hierarchical B-Ti₃C₂T_x/HCNS composite materials was obtained here with a superior electrochemical performance higher than that of single Ti₃C₂T_x in the present study, and many other reported Ti₃C₂T_x-containing materials in literature. In addition, an excellent electrochemical cycling stability with above 91% retention over 3000 cycles was also obtained for this new hybrid material. This work provides a new direction to promote the Ti₃C₂T_x-based materials for high-performance supercapacitors.