Strategically tailored CrCo2O4/MXene hybrid nano-architectures: Synergizing Dunn Model's insights with superior ionic conductivity for high-performance battery-type sustainable energy storage

Increasing global demand for sustainable technologies has triggered the researchers to develop innovative nanomaterials with superior attributes, including high energy/power density for efficient energy storage. In this endeavor, a facile hydrothermal approach was employed to synthesize CrCo₂O₄ (CCO) and a subsequent solvothermal-assisted approach was used to form composites using 10–40 % MXene/Ti₃C₂ (CCO-10, CCO-20, CCO-40), respectively. Among these, CCO-40 demonstrated a surface area of 39.46 m²/g, and a pore volume of 0.60 cm³/g. The electrochemical (EC) behavior was investigated via Dunn's model. Notably, galvanostatic charge-discharge revealed an impressive specific capacity (C_sc) of 1009 C/g for CCO-40 at a current density (J) of 5.8 A/g. Additionally, the electrode exhibited an energy density (E_d) of 70.0 Wh/kg at a power density (P_d) of 1470 W/kg, along with excellent cyclic stability, retaining 97 % capacity and 98 % coulombic efficiency after 3000 cycles. Electrochemical impedance spectroscopy showed a high ionic conductivity of 7.8 × 10⁻⁴ S/cm, and a diffusion coefficient of 2.59 × 10⁻⁵ cm²/K. Furthermore, the assembled asymmetric device demonstrated a C_sc of 383 C/g with an E_d of 74.64 Wh/kg and a P_d of 1674.05 W/kg at 2.3 A/g. These outstanding EC properties highlight the potential of CCO-40 as a highly efficient electrode material for next-generation energy solutions.