Government Subsidy Design for Digitalized Retired Battery Recycling in Green Ports: A Stackelberg Game Approach

With the acceleration of port electrification, the recycling of retired batteries has become an emerging challenge for green port development and sustainable maritime logistics. Digitalized recycling technologies can improve battery traceability, condition assessment, and recycling coordination, but their implementation requires substantial investment. This study investigates how government subsidy mechanisms influence digitalized retired battery recycling decisions in green ports. A digitalized reverse supply chain consisting of a battery manufacturer, a retailer, and green ports as end users is considered. Based on a two-stage Stackelberg game framework, two policy scenarios are developed and compared: a no-government-subsidy (NG) scenario and a government-subsidy (TG) scenario. The analytical results demonstrate that government subsidies can promote digital technology adoption, enhance recycling demand, and improve supply chain profitability when green ports have strong preferences for digitalized recycling services and when digital investment costs remain within a reasonable range. The numerical simulations further indicate that the effectiveness of subsidies depends on the interaction between green port preference and the manufacturer’s digital investment cost coefficient. The findings provide theoretical and managerial implications by revealing how government subsidies, green port digital preferences, and digital investment costs jointly influence recycling decisions and supply chain performance. Specifically, the results suggest that governments should design differentiated subsidy mechanisms according to digital technology maturity and market conditions, manufacturers should optimize digital investment strategies in reverse supply chains, and green ports should strengthen digital traceability and coordination capabilities to improve retired battery recycling efficiency.