A new cellulose-based separator improves lithium-ion transport, suppresses dendrites and enhances high-rate performance, potentially helping lithium-metal batteries achieve greater capacity and longer life.
Researchers at Hanabat National University have developed a biotite-infused cellulose (CBT) separator designed to improve the performance and stability of lithium-metal batteries, particularly during rapid charging and discharging. The approach could address key challenges that have limited the practical use of lithium-metal technology.
Lithium-metal batteries are attractive for next-generation energy storage because lithium metal offers considerably higher theoretical capacity than conventional graphite anodes. However, uneven lithium deposition can create dendrites, while electrolyte degradation can reduce performance and increase the risk of internal short circuits.
The new separator combines a porous cellulose structure with bikitate, a zeolite mineral. According to the researchers, this structure creates interconnected pathways that help lithium ions move more evenly through the cell. This can reduce polarisation and improve ion transport during demanding operating conditions.
The results indicate notable improvements at higher discharge rates. At 1C, cells using the CBT separator and conventional polyethylene separators delivered about 197 mAh g⁻¹. At 2C, however, the CBT-based cells retained 187 mAh g⁻¹, compared with 165 mAh g⁻¹ for the conventional separator.
Performance gains were also observed at 4C. The NCM90 cathode paired with the CBT separator reached around 163 mAh g⁻¹, compared with 115 mAh g⁻¹ using a conventional separator — an improvement of approximately 42%.
The separator also helped regulate lithium deposition. Real-time observations showed no visible dendrite growth, with lithium forming smoother and more compact layers and stripping more uniformly.
In cycling tests, cells retained roughly 60% of their capacity after 2,500 cycles at 2C/4C. The researchers say the separator could potentially be incorporated into existing battery manufacturing processes without redesigning the electrodes.
