Recycling of spent Li-ion batteries is crucial for achieving sustainable development of battery industry. Current recycling processes mainly focus on valuable metals but less attention has been paid to spent graphite, which generally ends up as secondary waste. In this study, a process for preparing graphene and recovering Li in anode as a by-product from spent graphite was developed. The key point was to re-charge the spent LIBs to generate lithium graphite intercalation compounds. The lithium graphite intercalation compounds were then subjected to a hydrolysis procedure and graphene could be produced through ultrasonic treatment via the expansion/micro-explosion mechanism. Experimental results demonstrated that 1–4 layered graphene could be efficiently produced when spent Li-ion batteries with beyond 50% capacity were re-charged. The prepared graphene showed high quantity containing few defects (I_D/I_G = 0.33, C/O = 13.2 by energy dispersive spectroscopy and C/O = 8.8 by X-ray photoelectron spectroscopy). In addition, Li was simultaneously recovered in the form of battery-grade lithium carbonate in the above process. Economic analysis indicated that the graphene production cost was extremely low ($540/ton) compared to that of commercial graphene.

废旧锂离子电池的回收对于实现电池行业的可持续发展至关重要。当前的回收过程主要集中在贵重金属上，但对废石墨的关注却很少，废石墨通常最终成为二次废物。在这项研究中，开发了一种制备石墨烯并从废石墨中回收阳极副产的Li的方法。关键是对用过的LIB重新充电以生成锂石墨插层化合物。然后对锂石墨插层化合物进行水解程序，并且可以通过膨胀/微爆炸机理通过超声处理来生产石墨烯。实验结果表明，对容量超过50％的废锂离子电池充电时，可以有效地生产1-4层石墨烯。_D / I _G  ＝ 0.33，通过能量色散光谱法的C / O ＝ 13.2，通过X射线光电子能谱法的C / O ＝ 8.8。另外，在上述过程中，以电池级碳酸锂的形式同时回收了Li。经济分析表明，与商业石墨烯相比，石墨烯的生产成本极低（540美元/吨）。