Investigating diffusion and convergence trajectory of hydrogen storage technology based on patent analysis.

Safe and flexible hydrogen storage technology (HST) emerges as a crucial element in driving the industrialization of hydrogen energy. Consequently, HSTs are being extensively investigated globally, with an increasing number diffusing beyond national boundaries through transnational patent applications. However, the absence of an evolutionary analysis constrains the exploration of technological opportunities in HST. In this study, we unveil the evolutionary trajectory and innovation trends of HST by analyzing its global diffusion and convergence network, utilizing patent family and IPC co-occurrence data spanning from 1993 to 2022. Our results indicate that the transnational diffusion of HST is concentrated in core countries. Japan and France emerged as dominant source countries, while China, Europe, Korea, and Canada were identified as main target countries for HST diffusion. Notably, in the past decade, China and France have experienced significant expansion in filing HST patents. However, China filed a relatively limited number of patent families, suggesting a varied level of engagement in transnational HST diffusion. Hydrogen fuel cells, storage alloys, vessels, and distribution systems constitute the primary technological domains of HST. In the initial stages, fuel cells and alloy materials dominated HST development, often converging with metal powders and heat treatment. However, since 2003, F17C, related to storage vessels, has evolved as a focal point of convergence, involving the integration of pressure tanks, filling and discharging systems, liquid transportation, gas purification, and rare earth materials. Overall, this research offers novel insights for strategizing future HST innovations. • The evolution of HST was evaluated through patent analysis. • Diffusion and convergence trajectory study provides a new perspective to understand HST's innovation trend. • The global diffusion network of HST tends to concentrate in few source and target countries. • Storage vessels and alloys are emerging directions of HST convergence. [ABSTRACT FROM AUTHOR]