The quirky thing about lithium-ion batteries is that they remain useful long after the device they power is retired. Letting them go to waste is, well, wasteful, and only spurs more lithium mining, which is terrible for the environment. That’s why repurposing—putting old batteries to use in new applications—has become an increasingly popular alternative. And thanks to China’s tinkerer ethic, low-cost labor, and willingness to tolerate lower standards in exchange for lower prices, the repurposing business is thriving.