With the shockingly high number of lithium-ion batteries, used in electric vehicles (EVs), discarded every year, it makes for a strong case against the technology, but scientists have found a way to reuse these batteries by bringing them back to life using molten salt.
What is the largest problem with lithium-ion batteries? Lithium batteries are barely recyclable and contribute to an annual waste total of 8 million tons, estimated to surpass 136,000 tons by 2036, which makes this an environmental problem. However, researchers might have discovered a way to fix it, per a press release from March 12.
Reviving dead lithium batteries
Specifically, scientists from the School of Materials Science and Engineering at Central South University in China have investigated molten salts because of their lower energy consumption and environmentally acceptable features. They placed them under high-temperature conditions, which allowed overcoming the limitations of traditional molten salts at low temperatures.
According to Gen Chen, PhD, an associate professor at the university and one of the authors of the study:
“These limitations hinder performance recovery in heavily damaged batteries, demanding urgent optimization of molten-salt systems. (…) Enhancing defect-repair capabilities while maintaining energy efficiency is crucial to broaden this method’s applicability across varied battery degradation levels.”
To address the issue, Chen’s team used a refined molten-salt approach leveraging high temperatures to boost cathode regeneration. By incorporating high-melting-point potassium chloride (KCl), they enhanced ion exchange and mass transport. This facilitated the complete recrystallization of severely degraded S-NCM cathodes, formed by combining nickel (Ni) and manganese (Mn) with lithium cobalt oxide (LCO).
Consequently, structural defects were repaired, impurity phases minimized, lost lithium restored, and battery stability and performance significantly improved. As Chen pointed out, not only did they manage to bring lithium-ion batteries back to life, but they came back retaining 81% of their power:
“After deep regeneration and recrystallization, the highly degraded S-NCM can restore the layered structure, and the surface oxygen vacancies and O-TM content can be reduced significantly. (…) Additionally, the upcycled cathode with single-crystalline structure effectively suppresses particle cracks and harmful side reactions during cycling, delivering a capacity retention of 81.2% after 200 cycles at 1oC [33.8°F], which is even significantly superior to standard C-NCM.”
Are there any alternatives to lithium batteries?
As it turns out, we may be on the threshold of saying goodbye to lithium in car batteries altogether, as scientists have discovered a high-energy sodium-ion cathode that could outperform the traditional lithium-ion ones and become a safer, more sustainable, and cost-effective alternative.
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