Synthesis of Ti3C2Tx(exf)@h‐BN@Co3O4 Hierarchical Structure: An Active Cathode for High‐Performing Solid‐State Supercapacitor and Density Functional Theory Calculations

A hierarchical heterostructure Ti₃C₂T_x(exf)@h-BN@Co₃O₄ has been synthesized. A flexible all-solid-state asymmetric supercapacitor was constructed by using this heterostructure as the cathode and biomass-derived porous carbon as the anode. To gain an in-depth understanding of the electronic band structure of Ti₃C₂@h-BN@Co₃O_4, computational investigations were carried out.

Herein, the synthesis of Ti₃C₂T_x(exf)@h-BN@Co₃O₄ and its electrochemical performances as an active cathode material in a flexible all-solid-state asymmetric supercapacitor (ASC) is presented. A hierarchical heterostructure has been created by integrating nanometer-thin exfoliated Ti₃C₂T_x(exf) MXene sheets with a 2-D layered hexagonal boron nitride (h-BN) and immobilizing Co₃O₄ nanorods on the surface. h-BN and Co₃O₄ offer rich redox features and highly conductive Ti₃C₂T _x facilitates the charge transfer process. To prepare the anode of ASC, a spent tea-derived porous carbon (PC) was used. An ASC device (Ti₃C₂T_x(exf)@h-BN@Co₃O₄//PC) was assembled with PVA-KOH gel-electrolyte. This device exhibited a specific capacitance of 105.8 F g⁻¹ at a current density of 0.5 A g⁻¹, an energy density of 33.0 W h kg⁻¹ at a power density of 375 W kg⁻¹, and retention of ≈90% of its initial capacitance and ≈85% of its Coulombic efficiency after 5000 charge-discharge cycles. To gain an in-depth understanding of the electronic band structure of Ti₃C₂@h-BN@Co₃O_4, computational investigations were carried out. The calculated value of quantum capacitance of Ti₃C₂@h-BN@Co₃O₄ was 59.16 μFcm⁻² at 2.67 V (positive bias). This work highlights the exceptional performance and durability of Ti₃C₂T_x(exf)@h-BN@Co₃O₄ ternary heterostructure and positions it as a highly promising candidate for next-generation supercapacitors.

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