Overview of present situation and technologies for the recovery of spent lithium-ion batteries

With the rapid population growth, economic development, and technological progress around the world today, energy consumption levels are becoming increasingly huge. Most of the energy consumed comes from coal, oil, natural gas, and other primary energy sources that lead to the greenhouse effect, acid rain, photochemical smog, and other environment problems. Therefore, the identification of greener energy resources has become humanity’s great challenge. To reduce the use of primary energy sources, new types of energy have been proposed that are associated with decreased environmental pollution. However, these new energy sources typically require effective storage equipment to facilitate the use of solar, wind or water-driven energy. Lithium-ion batteries (LIBs) were developed to store electrical energy, and due to their unique advantages, today they are widely used in portable devices, electric vehicles, and all kinds of electronic equipment. The advantages of LIBs include a high specific capacity, good cycle performance, and long lifespan. Although life on Earth is greener by the use of LIBs, with the rapidly increasing energy consumption, more spent LIBs are being produced, which contain a range of valuable metals (Cu, Al, Co, Mn, Ni, Li) and harmful substances (HF, organic substances). If these materials are not treated properly, much harm will result to both human beings and the natural environment, and this would also be a great waste of valuable metals. The recovery of spent LIBs has become a research hotspot among the scientific and business communities. To support the discovery of new methods and concepts in the recovery of spent LIBs, in this paper, we reviewed the various methods available and discussed their advantages and disadvantages in detail. Based on this review, we consider the approach that uses a combination of chemical and physical technologies for the recovery of spent LIBs to be the most promising.