However, with the rapid development of lithium batteries, their safety performance has become an increasingly important concern.
Traditional lithium batteries all use liquid electrolytes, and the properties of the liquid electrolyte directly affect its safety performance. Solid-state lithium batteries can solve some safety issues. However, due to the low conductivity between solid particles, the conductivity in solid-state batteries has always been unsatisfactory. Until research reports on solid-state-like electrolytes (MOF-IL) using MOFs as the main framework and lithium-ion liquids as ion transport objects opened up a new research perspective for solid-state batteries. Recently, Professor Pan Feng's team from the School of New Materials at Peking University Shenzhen Graduate School further improved the safety performance and ion transport performance of this type of solid-state electrolyte based on this perspective. The research results were recently published in Chemical Communications, entitled "Enhanced lithium dendrites suppressing capability enabled by a solid-like electrolyte with different-sized nanoparticles" (Chem. Commun., 2018.54.13060-13063; Nature Index journal DOI:10.1039/c8cc07476c), and were highlighted as the cover article.
Chem.Comm magazine cover
The team investigated the effect of particle size on the ionic conductor performance of MOF-IL batteries. Researchers combined two ionic conductors of different particle sizes. Compared to single-component ionic conductors, the mixed sizes effectively reduced the voids between electrolyte particles, increased contact points between electrolyte particles and between the electrolyte and lithium metal surfaces, resulting in more uniform lithium deposition and improved resistance to lithium dendrite growth. Furthermore, the increased ion-conducting channels also improved the electrolyte's conductivity. Batteries assembled with this type of solid-state electrolyte and commercially available cathode materials LiFePO4 and LiCoO2, and anode material lithium metal, exhibited considerable rate performance and cycle performance. The LiCoO2|electrolyte|Li battery had an initial capacity of 129 mAh g⁻¹ and retained 94.6% of its capacity after 100 cycles; the LiFePO4|electrolyte|Li battery had an initial capacity of 137 mAh g⁻¹ and retained 94.8% of its capacity after 100 cycles.
