Innovative fin designs for enhanced thermal performance in PCM-based thermal energy storage: a review

• Fin designs accelerate heat transfer, cutting phase change time by up to 98%. • A new framework compares fin performance, complexity, and manufacturability. • Hybrid and non-uniform fins align with heat flow for superior thermal storage. • Porous and fractal fins form efficient heat paths, boosting storage performance. • Future gains rely on experiments, optimization, and advanced manufacturing. The global transition to renewable energy necessitates advanced thermal energy storage (TES) to balance intermittent supply with constant demand. Latent heat thermal energy storage (LHTES) using phase change materials (PCMs) offers high energy density and isothermal operation but is hindered by low thermal conductivity. Fin integration is a key passive method to overcome this. While traditional fins provide foundational improvements, a paradigm shift is underway toward innovative, geometry-optimized designs. This review critically examines the evolution of fin configurations, from conventional longitudinal and annular fins to advanced non-uniform, fractal, vortex-generating, porous, morphing, and hybrid structures. We introduce and apply the Performance–Complexity–Manufacturability Trinity Framework (PCMTF), a novel holistic lens for evaluating these diverse designs, providing a systematic decision-support mechanism for selecting optimal fin configurations based on application-specific priorities. Our analysis reveals that strategic fin architectures synergistically enhance conduction and preserve natural convection, achieving melting/solidification time reductions of 40–98%. Cross-study synthesis supports a key design principle: future high-performance LHTES configurations should emphasize hybrid conduction networks that strategically distribute thermal conductivity, rather than relying on uniform fin arrays. The review identifies that future breakthroughs lie at the intersection of topology optimization, artificial intelligence, and additive manufacturing, enabling intelligent, application-specific thermal architectures. Finally, we outline persistent challenges, including standardization, long-term reliability, and techno-economic viability, and present a roadmap for research focused on multi-objective optimization to accelerate next-generation LHTES deployment.