Unveiling the functional roles of Critical Raw Materials in patents using Large Language Models

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Abstract:

Critical raw materials (CRMs) are increasingly becoming central inputs for EV, and more in general, green and digital technologies, but the innovation dynamics that shape material dependence and the emergence of alternative, more circular sourcing strategies is difficult to track at scale.
Using millions of patent abstracts from PATSTAT, in this paper we identify the function that critical raw materials play in inventions and assess whether new technological trajectories oriented toward secondary sourcing are emerging. To this aim, we combine keyword-based detection with a large-language-model classification pipeline that assigns each material-patent pair to four functional roles: use, refine, recycle, and remove. This function-sensitive approach moves beyond simple patent counts by identifying how materials contribute to technological development along the supply chain and at end-of-life, enabling a more nuanced view of innovation strategies.
While use-related patents remain dominant, recent growth in recycle and remove functions points to an expanding innovation frontier around recovery, circularity, and strategies consistent with secondary sourcing. Geographically, China leads across all functions, while an upward trend in recycling activity is observed across several advanced economies.
Moreover, we find a positive association between innovation in CRM refining, recycling and removal and innovation in CRM use, suggesting functional complementarities that can enable both technological progress and more sustainable material strategies rather than strict trade-offs. Finally, we propose a case study on battery CRM-intensive technologies. These results highlight the policy relevance of simultaneously supporting different CRM innovation strategies for building capabilities at different stages of the value chain to increase technological resilience, while also underscoring the need for effective real-time innovation monitoring in a rapidly changing global scenario. The novel and scalable framework we propose provides fills this gap by providing a practical tool to track material-related technological change and inform policy.