A 40-Year Bibliometric and Science Mapping Review of Optimization in Energy Storage Technologies

Amid accelerating demands for renewable integration and grid stability, the optimization of energy storage technologies (ESTs) has become a cornerstone of sustainable energy systems. This study presents a comprehensive bibliometric and science mapping review of 3,750 publications (1985-2024), employing ScientoPy for performance analysis and VOSviewer for network visualization. Unlike prior bibliometric reviews, which have typically focused on single technologies (e.g., lithium-ion batteries) or limited timescales (<20 years), this work provides the first longitudinal, cross-technology mapping of EST optimization spanning four decades, thereby filling a critical gap in the literature. The results reveal a steep growth in scholarly output after 2015, driven by advances in lithium-ion batteries, supercapacitors, and IoT-enabled monitoring systems. "Optimization" emerges as the dominant axis, frequently intersecting with multi-objective optimization, smart grid integration, and thermal storage. Influential outlets (Journal of Energy Storage, Energy, and Energies), leading nations (China, United States, India), and prominent institutions (e.g., North China Electric Power University) anchor global research networks. Keyword co-occurrence and thematic evolution highlight a shift from early material-level studies toward system-level approaches, with emerging frontiers in microgrid resilience, digital control, and cyber-physical energy systems. By consolidating past knowledge and identifying research gaps, this review provides a strategic roadmap for advancing scalable, intelligent, and sustainable ESTs, offering actionable insights for researchers, practitioners, and policymakers driving the global decarbonization agenda.