Generalized interfacial assembly of 2D mesoporous heterostructures for high-energy solid-state micro-supercapacitors

2D materials have garnered considerable interest in various applications from catalysis to energy storage. However, the self-stacking and poor air stability of 2D materials (e.g., MXene) leads to serious performance degradation, in particular, of micro-supercapacitors (MSCs) with narrow working voltage and low energy density. Here, a universal confined interfacial assembly strategy is demonstrated for controllably synthesizing a series of 2D mesoporous heterostructures for high-voltage and high-energy ionogel-based MSCs. This assembly process reveals accurate controllability and extraordinary versatility, endowing the 2D mesoporous heterostructures with highly adjustable mesopore size (7-22 nm), tunable thickness (15-29 nm), variable carbon precursors (including oligochitosan, glucose, and sucrose), and replaceable 2D substrates (e.g., MXene, graphene, BN, and MoS${}_2$). As a proof of concept, the 2D mesoporous carbon@MXene based MSCs with ionic liquid ionogel electrolyte deliver ultrahigh voltage of 3.7 V, superior areal energy density of 181.3 µWh cm${}^{-2}$, excellent flexibility with 99% of capacitance retention at 180°, and excellent modular self-integration for variable voltage/capacitance output, surpassing most reported MXene based MSCs. Therefore, this work will open a novel available paradigm for scalable fabrication of 2D mesoporous materials to target high-performance and functional microscale power source. (© 2024 Wiley‐VCH GmbH)