Introduction: The Hidden Treasure in E-Waste With global e-waste surpassing 70 million tons annually by 2025, old household gadgets like broken desk fans, discarded toys, and outdated handheld vacuums often end up in landfills. Yet their core components—18650, 21700, and other lithium batteries—hold untapped potential. These batteries, typically with 2000mAh+ capacity, can be transformed into emergency power […]