Robust and Elastic Bioinspired MXene-Coated Foams with Enhanced Energy Storage and Conversion Capabilities

Abstract

Constructing highly porous structures using Ti3C2Tx MXene provides a promising strategy toward achieving low density, high specific surface area, and shorter ion/molecule transport paths. However, the weak MXene-MXene or MXene-substrate interactions hinder the development of ultra-robust and elastic MXene-based architectures. To address this issue, a bio-inspired strategy is developed to effectively adhere the MXene nanosheets onto melamine foam via covalent and hydrogen bonding interactions through polyethyleneimine/polydopamine-modification. The enhanced interactions contribute to high MXene loading (≈94 wt.%) and reversible compressibility even after 10 000 compression/release cycles at 80% strain. The compressible supercapacitor device assembled from this foam exhibits high energy storage capability (119 F g−1 at 2 mV s−1) with capacitance retention of ≈93% after 1000 compression/release cycles at 50% strain. Moreover, the presence of polydopamine and MXene enable the absorption of light in the UV–Vis and near-IR regions, respectively, inducing photothermal conversion functionality, with an evaporation rate of ≈1.5 kg m−2 h−1 and ≈89% solar evaporation efficiency under one sun illumination. It is envisaged that this bio-inspired chemical modification offers a versatile strategy for the assembly of MXene nanosheets onto different substrates for various applications, such as electromagnetic interference shielding, energy storage, and conversion.