The demand for recovering lithium-ion battery components is increasing due to the surging volume of spent lithium-ion batteries. Graphite is commonly used as the anode material in lithium-ion batteries, and recovering graphite from spent anodes has attracted significant attention. Currently, acid leaching is used to simultaneously recover metal impurities and graphite from anodes, but the subsequent disposal of acidic waste pollutes the environment, contradicting green chemistry principles. This work reports a CO₂ roasting process that repairs the graphite structure by annealing spent graphite in CO₂. This converts metal impurities into water-soluble carbonates that can be removed via aqueous washing. CO₂ roasting more effectively removes impurities from graphite compared to N₂ roasting, and also enhances the rate performance of recycled graphite. At high current densities of 1C and 2C, the regenerated graphite achieved discharge capacities of 366 and 332 mA h g⁻¹, respectively, comparable to commercial graphite. This environmentally friendly process recovers graphite anodes without requiring acid leaching, providing a new approach for designing high-rate recycled graphite anodes.

中文翻译：

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通过简单的热处理方法直接再生废石墨负极材料

由于废旧锂离子电池数量激增，回收锂离子电池组件的需求不断增加。石墨通常用作锂离子电池的负极材料，从废负极中回收石墨引起了人们的广泛关注。目前，采用酸浸法同时回收阳极中的金属杂质和石墨，但随后的酸性废物处理会污染环境，违背了绿色化学原则。这项工作报道了一种CO _{2焙烧工艺，通过在CO 2}中对废石墨进行退火来修复石墨结构。这会将金属杂质转化为水溶性碳酸盐，可以通过水洗去除。与N ₂焙烧相比， CO ₂焙烧更有效地去除石墨中的杂质，并且还提高了再生石墨的倍率性能。在1C和2C的高电流密度下，再生石墨分别实现了366和332 mA hg ^-1的放电容量，与商业石墨相当。这种环保工艺无需酸浸即可回收石墨阳极，为设计高效率回收石墨阳极提供了一种新方法。