MELBOURNE, Jan. 21 (Xinhua) -- Researchers in Australia have developed an environmentally friendly method to recover critical metals from spent lithium-ion batteries.

The process offers a safer alternative to traditional high-temperature or chemical-intensive recycling methods, said a statement from Australia's Monash University on Tuesday.

A Monash-led team said the new technique uses a mild, sustainable deep eutectic solvent combined with integrated chemical and electrochemical leaching to extract high-purity nickel, cobalt, manganese and lithium from spent lithium-ion batteries.

The method achieves more than 95 percent recovery even from industrial-grade "black mass," a complex battery waste containing mixed battery chemistries and impurities, according to the research, published in Sustainable Materials and Technologies.

"This is the first report of selective recovery of high-purity Ni, Co, Mn, and Li from spent battery waste using a mild solvent," said Parama Chakraborty Banerjee, principal supervisor and project lead from the Monash University Department of Chemical and Biological Engineering.

"Our process not only provides a safer, greener alternative for recycling lithium-ion batteries but also opens pathways to recover valuable metals from other electronic wastes and mine tailings," she said.

Globally, about 500,000 tonnes of spent lithium-ion batteries have accumulated, with only around 10 percent fully recycled in Australia.

Spent lithium-ion batteries often end up in landfills, leaching toxins into soil, groundwater and food chain with serious health risks, but contain valuable strategic metals.