Spatiotemporal and Multilayer Trade Network Patterns of the Global Cobalt Cycle

Area of Science:

• Industrial Ecology
• Network Science
• Supply Chain Analysis

Background:

• Growing demand for critical materials in renewable energy and low-carbon technologies.
• Previous trade flow studies lacked spatiotemporal coverage and end-use product inclusion.
• Existing network models often simplified life cycle stages into single layers.

Purpose of the Study:

• To analyze the spatiotemporal and multilayer trade network patterns of the global cobalt cycle from 1988 to 2020.
• To identify key players and structural changes in international cobalt trade.
• To investigate the interconnectedness of different life cycle stages in cobalt supply chains.

Main Methods:

• Integrated material flow analysis (MFA) with complex network analysis (CNA).
• Developed a multilayer network framework to model the global cobalt cycle.
• Analyzed trade data spanning 1988 to 2020.

Main Results:

• Observed substantial growth and structural evolution in global cobalt trade over 32 years.
• Identified China, Germany, and the United States as pivotal actors in various trade network layers.
• Found strengthening interlayer relationships among alloys, batteries, and materials, indicating synergistic trade.
• Highlighted a disconnect between concentrated cobalt ore exporters and later life cycle stages, causing trade volatility.

Conclusions:

• The multilayer network model provides a robust framework for analyzing critical material trade dynamics.
• Concentration in ore export and limited participation in downstream stages create vulnerabilities in the cobalt supply chain.
• The methodology can be applied to other critical materials essential for the green energy transition.