Progress and prospects of cold thermal energy storage for liquid air energy storage systems – A critical review

Electrical energy storage plays a vital role in enabling renewable energy integration and achieving decarbonization targets under the Paris Agreement. Liquid air energy storage (LAES) is a promising large-scale, long-duration storage technology due to its scalability, site flexibility, and high energy density. A crucial component of LAES performance is the cold thermal energy storage (CTES), which recovers cryogenic exergy during air regasification to recovery during the liquefaction phase, significantly improving the round trip efficiency. This paper presents a comprehensive and critical review of CTES technologies for LAES, aiming to identify optimal design approaches based on current literature and industrial practices. The review covers sensible and latent heat storage systems, hybrid and cascade configurations, and advanced geometries, assessed through thermodynamic and techno-economic performance indicators. Our analysis finds that packed beds with sensible heat materials are the most mature and cost-effective option, while phase change material-based systems offer higher efficiency potential—achieving round-trip efficiency improvements of up to 55 %—but face challenges in material cost, availability, and scalability. Hybrid and cascade configurations show promise in simulations, though experimental data remain limited. Cold storage losses are shown to impact round-trip efficiency up to seven times more than heat losses, highlighting the strategic importance of CTES optimization. The authors identify key research needs in dynamic system modeling, scalable material development, and lifecycle techno-economic assessment. Addressing these gaps will be critical to advancing CTES as a performance-enhancing and cost-effective component of next-generation LAES systems.