Advanced energy materials for a sustainable future: Phase change materials, thermal energy storage, solar thermal integration, numerical modelling, techno-economic assessment, environmental impact, and AI-assisted materials design

Decarbonising heat is one of the most under-addressed pillars of the global energy transition: thermal applications absorb the majority of primary energy in buildings and industry yet remain dominated by fossil fuels. Advanced energy materials and phase-change materials (PCMs) integrated into thermal energy storage (TES) systems provide a route to bridge the temporal mismatch between renewable thermal generation and demand at energy densities well above those of sensible storage. This review critically synthesises the materials chemistry, engineering integration, modelling, techno-economic, and life-cycle dimensions of advanced energy materials for sustainable latent-heat thermal energy storage; sensible and thermochemical storage are positioned but not reviewed at comparable depth. This review organises 131 peer-reviewed sources (predominantly 2020–2026), selected through a fully documented PRISMA 2020 workflow (searches of 12 January 2026, updated 30 June 2026), and provides a comparative analysis of organic, inorganic, eutectic, and composite PCMs; thermal-conductivity-enhancement strategies (expanded graphite, graphene, carbon nanotubes, carbon fibres, biochar, MXenes, metal foams, ceramic and hybrid fillers); microencapsulation, macro encapsulation and shape-stabilisation routes; and the resulting interfacial-, percolation- and stability-related trade-offs. Solar-thermal integration in collectors, photovoltaic–thermal cooling, building envelopes, industrial waste-heat recovery and emerging seasonal thermal batteries is examined, emphasising that material-level gains are realised only when system architecture, heat-exchanger design and control strategy are co-optimised. Numerical modelling from molecular dynamics to multiphysics computational fluid dynamics and physics-informed neural network surrogates is appraised alongside the recent emergence of digital twins for live TES operation. Techno-economic assessments and cradle-to-grave life-cycle analyses are critically evaluated, arguing that the label sustainable is meaningful only when supported by quantitative LCA, recyclability, toxicity, and economic feasibility evidence. A dedicated section reviews artificial-intelligence and machine-learning routes to PCM discovery, noting the persistent scarcity of standardised PCM/TES datasets. The review closes by mapping the principal research gaps and proposing an integrated materials-system-sustainability research agenda.