The Engineer – Solid state battery breakthrough from pan-Asian team

According to the team, which included contributors from across several Asian universities, they have developed a new generation of solid-state electrolytes (SSEs) for lithium-metal batteries (LMBs), greatly improving both safety and performance. SSE technology could be transformative, as it promises enhanced energy density compared with the lithium-ion batteries in wide use today, as well as removing the risk of thermal runaway due to dendrite formation. 

The new approach to SSEs saw the team combining a class of porous called ionic covalent organic frameworks (iCOFs) with a type of polymer called poly(ionic liquid) (PIL) for fabricating solvent- and plasticiser-free SSEs. This new iCOF/PIL composite SSE achieved high ionic conductivity (up to 1.50 x 10−3 S cm−1) and lithium-ion transport capability (> 0.80) at room temperature.  

Using this advanced SSE, the team then fabricated a LMB full cell made of composite SSEs and a LiFePO4 composite cathode. In testing, the cell demonstrated an initial discharge capacity of 141.5mAh g−1 at 1C and room temperature, with a capacity retention of 87 per cent over 800 cycles. The study, recently published in Advanced Energy Materials, was a collaboration between researchers at HKUST, Shanghai Jiao Tong University and Zhejiang University in Mainland China and Hanyang University in South Korea.

“Our breakthrough approach demonstrates stable cell operation and shows a high reversible capacity in all-solid-state LMBs for the first time,” said  Professor KIM Yoonseob, assistant professor of the Department of Chemical and Biological Engineering at HKUST. 

“It unleashes great potential of iCOFs for electrochemical energy storage devices, opening up new paths forward for wider adoption of all-solid-state LMBs in a variety of applications, from electric vehicles to portable electronics and power grids.”