User-database-driven projection framework of mobile phone lithium-ion battery waste

Projecting mobile phone-based lithium-ion battery (MLIB) waste in developing countries such as India is challenging due to diverse and informal sources of device entry into the market. Unmanaged MLIB waste presents a significant threat to the sustainability of energy storage systems, as it increases reliance on virgin raw materials and weakens the principles of a circular economy. In India, informal systems contribute nearly 70% of mobile phone circulation, yet these dominant flows are often overlooked in conventional waste assessment and forecasting approaches. Conventional sales data-based estimation methods capture only formal supply channels and therefore fail to account for grey market imports and refurbished devices. As a result, current approaches do not accurately reflect the actual volume of MLIB waste generated. Mobile phone user database (UDB) is an important way for the assessment of such waste. The current study highlights the critical role of informal waste handlers in the quantification of MLIBs. Two primary parameters were considered: (1) mobile phone SIM UDB on single- and dual-SIM mobile phone usage and (2) stakeholder surveys conducted within a representative model area. Integrating stakeholder insights with SIM-based UDB enables a more accurate estimation of MLIB waste at both national and global scales.