ENGINEERING TECHNOLOGY

“Three birds with one stone” realizes the “regeneration” of cathode materials of waste lithium cobalt oxide batteries


Recently, Zhang Yunxia, researcher of the Institute of Solid State Physics, Hefei Institute of Physical Sciences, Chinese Academy of Sciences, and Han Miaomiao, associate professor of Huzhou Normal University, can effectively recycle and upgrade the cathode material of waste lithium cobalt oxide battery to high-performance high-pressure lithium cobalt oxide cathode material through a simple “killing three birds with one stone” solid phase sintering strategy. On August 17, the relevant research results were published in Advanced Energy Materials.

Schematic diagram of the recycling process of cathode materials of waste lithium cobalt oxide batteries. Photo courtesy of Institute of Solid State Physics, Hefei Institute of Physical Sciences, Chinese Academy of Sciences

Lithium-ion batteries have the characteristics of high energy density, long life, low cost and low self-discharge, and are widely used in portable electronic products, electric vehicles, grid-level energy storage systems and other fields. Among them, as a typical cathode material for lithium-ion batteries, lithium cobalt oxide occupies a dominant position in portable electronic devices due to its inherent high energy density and convenient large-scale production. More than 100,000 tons of used lithium-ion batteries are produced in discarded portable electronic products around the world every year, and if not handled properly, it will cause serious environmental hazards and a huge waste of precious metal resources. At the same time, as the demand for battery energy density continues to increase, increasing the cut-off voltage has become one of the most effective strategies to improve energy density. Therefore, if the waste lithium cobalt oxide is recycled into high-pressure lithium cobaltate, it not only realizes the sustainable utilization of metal resources, but also meets the development trend of high-pressure lithium cobalt oxide cathode materials.

The traditional recovery technology is mainly based on pyrometallurgy and hydrometallurgy, and the corresponding precursors are prepared by extracting valuable metal components. However, both processes lack economic viability and environmental friendliness. Therefore, it is urgent to explore a green, energy-saving and lossless direct regeneration strategy for lithium-ion batteries.

In this study, the researchers used the one-pot solid phase sintering method to simultaneously realize the triple effect coupling of composition/structural defect repair, outer surface reconstruction and element doping, so as to achieve the effect of “killing three birds with one stone” and upgrading the waste lithium cobalt oxide to a high-pressure lithium cobalt oxide cathode material. The obtained high-voltage lithium cobalt oxide cathode material has a capacity of 188.2 mAh per gram at a cut-off voltage of 4.5 volts; The material has excellent cycling performance, with a capacity retention rate of 92.5% after 100 cycles and 86.4% after 300 cycles.

At the same time, waste lithium cobalt oxide cathode materials from different manufacturers or different failure degrees can be effectively upgraded to high-performance high-pressure lithium cobalt oxide cathode materials, which proves that the solid phase sintering strategy of “killing three birds with one stone” is universal. In addition, the researchers used in situ X-ray diffraction and density functional theory theoretical calculations to explore the intrinsic structural evolution and potential regeneration mechanism of materials during charge and discharge.

According to the researchers, the work is expected to provide new ideas for the recycling and upcycling of waste lithium-ion batteries to produce high-energy-density batteries with long-term cycle stability. (Source: Wang Min, China Science News)

Related paper information:https://doi.org/10.1002/aenm.202302058



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