Magnesium-based nanocomposites reinforced with 2D materials for advanced energy storage and environmental applications: A review

Magnesium (Mg)-based nanocomposites reinforced with two-dimensional (2D) materials have emerged as promising multifunctional platforms for energy storage and environmental remediation owing to their low cost, natural abundance, tunable surface chemistry, and unique interfacial properties. However, despite extensive research on MgO, magnesium alloy, and 2D-material based systems, current knowledge remains fragmented, and the fundamental relationships between interfacial engineering, defect chemistry, and functional performance have not been systematically evaluated. This review critically analyzes recent advances in Mg-based nanocomposites reinforced with 2D materials (graphene derivatives, MXenes, and LDHs), with emphasis on synthesis strategies, interface formation mechanisms, defect modulation, and structure-property relationships. A comprehensive analysis of peer-reviewed studies published from 2010 to 2025 was conducted to critically assess advances in synthesis strategies, interfacial engineering, defect modulation, and their impact on the functional performance of Mg-based/2D nanocomposites. Representative performances include specific capacitances up to 759 F g⁻¹, energy densities of 42.7 Wh kg⁻¹, adsorption capacities exceeding 1275 mg g⁻¹ for organic pollutants, photocatalytic degradation efficiencies approaching 99% under optimized conditions and CO₂ capture capacities up to 31.5 wt%. Mechanistic insights derived from experimental and theoretical investigations highlight the pivotal roles of oxygen vacancies, heterointerface-induced charge redistribution, band structure modulation, and defect-mediated charge transport in governing material performance. Despite these advances, critical challenges remain, including corrosion susceptibility, oxidation-induced degradation, nanosheet restacking, interfacial instability, limited reproducibility, and the lack of scalable and economically viable manufacturing routes. Contradictory performance trends arising from variations in synthesis protocols, defect concentrations, and testing methodologies are also critically examined. Furthermore, this review discusses degradation mechanisms, scalability limitations, operando characterization techniques, and emerging artificial intelligence/machine learning-assisted materials design strategies. Finally, future directions involving rational interface engineering, controlled defect modulation, data-driven material discovery, and industrial-scale translation are proposed to accelerate the practical deployment of Mg-based/2D nanocomposites in next-generation energy and environmental technologies.