Chinese researchers invent new material for solid lithium batteries

QINGDAO, Aug. 26 (Xinhua) -- Chinese researchers have created a new cathode material to increase the cycle-life of all-solid-state lithium batteries, potentially improving their viability for commercial applications.

The research was recently published in the journal Nature Energy.

The research team from Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT), Chinese Academy of Sciences, explained to Xinhua on Monday that all-solid-state lithium batteries using solid electrolytes are less likely to leak and burn than conventional liquid lithium-ion batteries, which are widely used in electric vehicles, mobile phones and computers.

According to Ju Jiangwei, a Ph.D. from QIBEBT and the corresponding author of the research, their new creation empowered all-solid-state lithium batteries with high conductivity, high specific discharge capacity, small volume change, high energy density, and long cycle life compared with previous solid lithium batteries.

This new homogeneous cathode material, which will enable solid lithium batteries to have higher safety and superior performance, has not yet been named.

Ju said the new material achieves over 1,000 times the electronic and ionic conductivity of traditional battery cathode materials. It can smoothly undergo charge and discharge cycles without conductive additives, which simplifies the battery preparation process and also improves the performance of the all-solid-state lithium battery.

Ju also stressed that the new material's 1.2 percent volume change during charge and discharge is more conducive to maintaining the stability of the battery structure than the traditional material, which has a volume change of over 2.6 percent. Even after 5,000 charge and discharge cycles, the new material battery still retains 80 percent of its initial capacity.

The research also mentioned that the new material battery's energy density of up to 390 watt-hours per kilogram reflects a longer battery life, 1.3 times that of the most advanced lithium-ion batteries on the market.

All-solid-state lithium batteries have a huge market in the direction of power batteries, and their successful commercialization will provide strong momentum for the national new energy automobile industry and low-altitude economy.

According to the research team, all-solid-state lithium batteries are a new generation of energy storage technology that can store electricity from wind and solar energy. These batteries can help achieve China's "dual carbon" strategic goals, actively promote the green and low-carbon transformation of China's economy and society, and drive green technology innovation and industrial development.

The new material's parent material was initially noticed in an article published by Nobel Prize winner John Bannister Goodenough in 2008. The research team found it would have the potential for excellent ionic conductivity. Due to its complex elemental composition, it took the team two years to synthesize this parent material.

"Contrary to our expectations, the ionic conductivity of this material is low, while the electronic conductivity is high. Therefore, we first improved the ionic conductivity by doping it with germanium, then tried to enhance the electronic conductivity by replacing sulfur with selenium, and finally obtained the new material," Ju said.

The research team also found that replacing germanium with cheap and abundant silicon can greatly reduce the battery's cost and contribute to the commercialization of all-solid-state lithium batteries.

"We are currently preparing this material in small batches and expect to achieve large-scale production in two to three years. In terms of cost, we hope to develop a new material with less lithium in the future. If successful, the cost of sulfide solid-state lithium batteries can be reduced to 30 percent of that of liquid lithium batteries," Ju added.

Ju noted the research team will also focus on the recycling of all-solid-state lithium batteries in future research.