Highly Self-Healable 3D Microsupercapacitor with MXene–Graphene Composite Aerogel

TLDR

High‑performance 3D microsupercapacitors enhance energy‑storage capability. The study aims to fabricate a self‑healable 3D microsupercapacitor by combining a MXene‑graphene aerogel electrode with a self‑healing polyurethane shell to resist mechanical damage. The MXene‑rGO aerogel, leveraging rGO’s large surface area and MXene’s conductivity, prevents lamella restacking and mitigates MXene oxidation, while the polyurethane shell enables self‑healing. The device achieves 34.6 mF cm⁻² specific capacitance at 1 mV s⁻¹, retains 91 % after 15 000 cycles, and recovers 81.7 % of its capacitance after five self‑healing cycles, confirming outstanding performance and durability.

Abstract

High-performance microsupercapacitors (MSCs) with three-dimensional (3D) structure provide an effective approach to improve the ability of energy storage. Because the electrodes with 3D structure are generally easily destroyed under mechanical deformation in practical applications, we fabricated a self-healable 3D MSC consisting of MXene (Ti3C2T x)-graphene (reduced graphene oxide, rGO) composite aerogel electrode by wrapping it with a self-healing polyurethane as an outer shell. The MXene-rGO composite aerogel combining large specific surface area of rGO and high conductivity of the MXene can not only prevent the self-restacking of the lamella structure but also resist the poor oxidization of MXene to a degree. The MSC based on a 3D MXene-rGO aerogel delivers a large area specific capacitance of 34.6 mF cm-2 at a scan rate of 1 mV s-1 and an outstanding cycling performance with a capacitance retention up to 91% over 15 000 cycles. The 3D MSC presents an excellent self-healing ability with specific capacitance retention of 81.7% after the fifth healing. The preparation of this self-healable 3D MSC can provide a method for designing and manufacturing next-generation long-life multifunctional electronic devices further to meet the requirements of sustainable development.