Evolution and security drivers of the global lithium-cobalt-nickel multilayer trade network

Against the backdrop of accelerated restructuring of global critical mineral allocation, profound reorganization of industrial and supply chains, and the coordinated advancement of the green and low-carbon energy transition, the evolution and coupling relationships of the trade networks of lithium, cobalt, and nickel — as core minerals in the power battery industry chain — have become important issues affecting the security and resilience of critical mineral supply chains. Existing studies mainly examine trade network structures and driving factors from the perspective of a single mineral, while paying insufficient attention to the multilayer network structure formed by lithium, cobalt, and nickel through technological coupling, demand linkage, and trade interdependence, as well as the cross-layer risk transmission mechanisms embedded therein. To fill this gap, a global multilayer lithium-cobalt-nickel trade network is constructed based on bilateral trade data from 2010 to 2024, and complex network analysis, the XGBoost model, and the SHAP method are employed to systematically investigate its evolutionary characteristics, security drivers, and cross-layer spillover effects. The results show that: ① the trade networks of the three minerals exhibit an overall intensive evolutionary trend characterized by “node contraction and linkage enhancement”; the core-periphery structure is continuously reinforced, and “small-world” properties become more pronounced, indicating that global trade ties are increasingly concentrated among a small number of core countries. ② Economic scale and geographical distance remain the fundamental drivers of trade link formation. Economies’ structural position within their own specific-layer network constitutes the primary driver for establishing such connections, while resource endowment, logistics connectivity, institutional environment, price signals, and the growth of new energy vehicle demand jointly shape the differentiated evolution paths of critical mineral trade networks. ③ Significant and asymmetric cross-layer spillover effects are identified in the multilayer network: lithium acts as the core entity facilitating cross-layer integration, followed by nickel, while the impact of cobalt remains relatively moderate. Eigenvector centrality serves as the primary conduit for cross-layer spillover, with betweenness centrality playing a supportive role, whereas betweenness centrality dominates trade organization within individual mineral layers. Furthermore, the bridging control and structural embedding influence wielded by nations within the supply chain have emerged as the core dynamics driving and reshaping the global landscape of critical mineral trade. ④ The cross-layer model consistently outperforms the benchmark model, with the combined three-layer model demonstrating the highest stability across different time periods, indicating that the lithium-cobalt-nickel trade network exhibits significant systemic coupling characteristics and that critical mineral supply chain security should be assessed from a multi-mineral collaborative perspective. The findings provide theoretical support and policy implications for safeguarding China’s critical mineral security, improving supply chain risk warning systems, optimizing strategic reserves, and enhancing the capacity for global resource allocation.