3D cellular lattice like-Ti₃C₂ MXene based aerogels embedded with metal selenides particles for energy storage and water splitting applications

In this research, we have designed novel three-dimensional (3D) Ti₃C₂ MXene/rGO composite aerogels (MGA) integrated with octahedron-like NiSe₂ (NS), with different mass loadings of MXene (20 wt% and 40 wt%). Resultant aerogels developed into a cellular lattice like network that significantly improved the contact area among active material and electrolyte. 3D spongy scaffold of MGA boosted the mass diffusion rate, and good electrical conductivity of MXene and rGO provided fast transport of charges during the electrochemical tests, which endowed superior supercapacitor and water splitting performances. Electrode with optimized MXene/rGO ratio i.e., NSMGA-40, exhibited a remarkable specific capacity of 289.7 mAh g⁻¹ at current density of 1 A g⁻¹ and excellent durability of 92.5% over 5000 charge/discharge cycles at 12 A g⁻¹ in a three electrode system for supercapacitor. Meanwhile, as a bifunctional electrocatalyst, NSMGA-40 required a low overpotential of 97 mV and 262 mV to reach 10 mA cm⁻² for HER and OER activity, respectively, in alkaline media. The values of Tafel slopes were as small as 89 mV dec⁻¹ (HER) and 75 mV dec⁻¹ (OER), signifying accelerated electron-transfer kinetics. Furthermore, in both cases, NSMGA-40 electrocatalyst withstood a long-term stability test of 10 h. Hence, the obtained results can be manifested for the structural and componential engineering that maximizes the synergetic effects from Ti₃C₂ MXene, rGO, and NS. Indeed, our fabricated aerogels offer a valuable reference for the fabrication of 3D multicomponent electrode materials for energy storage and conversion applications.