Scientists develop environmentally friendly methods to reduce the cost of recycling lithium batteries

According to foreign media reports, most current lithium batteries use a rare and expensive metal called cobalt as part of the cathode composition, but mining this material requires a huge environmental price. One of the more environmentally friendly alternatives is called lithium phosphate ion, and a new breakthrough can further improve the environmental performance of this cathode material, once it is used up, it can be restored to its original state, and the energy used is only the current method a small part of. This research was conducted by nano-engineers at the University of California, San Diego, and focused on the recovery technology of cathode batteries made of lithium iron phosphate. By abandoning heavy metals such as nickel and cobalt, these types of batteries can help prevent degradation of the landscape and water sources where these materials are mined, and exposure of workers to hazardous conditions. People's awareness of cobalt-related issues has continued to increase, which has promoted the transformation of the industry. Many people are looking for alternative battery designs, including large companies such as IBM and Tesla. They started selling Model 3 using lithium iron phosphate batteries this year. These batteries are safer, longer lasting, and cheaper to process, but one disadvantage is that once they are used up, the cost of recycling is high. 'It's not cost-effective to recycle them,' said Zheng Chen, a professor of nanoengineering at the University of California, San Diego. 'This is the same dilemma as plastics-materials are cheap, but the method of recycling them is not cheap.' The focus of the recycling breakthrough is the several mechanisms behind the degradation of lithium iron phosphate batteries. When they are recycled, this process will promote structural changes. With the loss of lithium ions, vacancies appear in the cathode, and iron and lithium ions will also exchange positions in the crystal structure. This entrains lithium ions, preventing them from circulating in the battery. The team took the commercially available lithium iron phosphate battery unit and exhausted it to half of its storage capacity. Then, they disassembled the battery and soaked the resulting powder in a solution containing lithium salt and citric acid, then rinsed it, dried it, and heated it at a temperature of about 60 to 80°C. Then the powder was made into a new cathode and tested in button batteries and pouch batteries. The research team found that its performance returned to its original state. This is because this recycling technology not only supplements the battery’s lithium ion inventory, but also allows lithium and iron ions to return to their original positions in the cathode structure. This is due to the addition of citric acid, which supplies electrons to iron ions, reducing the positive charge that normally repels iron ions from moving to their original positions. The result of all this is that lithium ions can be released and circulate in the battery again. According to the team's research, compared with the current method of recycling lithium phosphate batteries, its technology consumes 80% to 90% less energy and reduces greenhouse gas emissions by about 75%. Although this is a good start, the team stated that further research is needed to determine the overall environmental footprint of collecting and transporting large quantities of these batteries. 'Finding out how to optimize these processes is the next challenge,' Zheng Chen said. 'And this will bring this recycling process closer to industry adoption.' The research was published in the 'Joule' magazine. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete.