Phase change material-based thermal energy storage: a review of current trends, research evolution, and growing role of artificial intelligence

Thermal energy storage (TES) using phase change material (PCM) is one of the key technologies to improve energy efficiency and integrate renewable energy. This study aims to systematically map the research evolution, emerging themes, major contributors, and technological developments in PCM-based TES research from 2000 to 2025. A PRISMA-based bibliometric analysis was conducted using 5612 publications retrieved from the Scopus database and analyzed using Bibliometrix and VOSviewer. The analysis examines publication trends, leading countries and journals, collaboration networks, citation patterns, keyword co-occurrence, and thematic evolution. With an above 60% share of the publications after 2018, it shows the rapid development in this field, with China and India being the main contributors. The research areas have developed from the fundamental characterization of PCMs to nano- and composite PCMs, heat transfer enhancement, battery thermal management, building energy applications, and sustainable energy systems. The application of artificial intelligence and machine learning in TES modeling, prediction, optimization, and intelligent control is shown in emerging research clusters, which demonstrates a growing trend. The findings identify key research directions and gaps, particularly in optimizing nano/composite PCM formulations, validating PCM performance under realistic operating conditions, and developing experimentally validated AI/ML models. This review offers a structured knowledge of the development of PCM-based TES research and identifies some specific opportunities for the development of efficient, reliable, and application-oriented thermal energy storage technologies.