吉林大学于吉红小组揭示了固态电池用表面导电锂超离子导体。这一研究成果发表在2025年3月24日出版的国际学术期刊《美国化学会杂志》上。

该课题组人员发现了一类通过表面化学吸附获得的表面导电锂超离子导体。惰性底物与配体结合后，表面原子成为锂盐解离的结合位点和表面Li⁺快速扩散的跳跃位点，使惰性材料转变为表面导电的Li⁺导体。利用二维TiO₂纳米片作为概念证明，研究小组发现乙醇酸乙酯化学吸附的TiO₂显著增强了锂盐解离，促进了表面氧原子之间的快速Li⁺跳跃，实现了3.61×10^–7 cm²·V^–1·s^–1的高表面离子迁移率，比Li₇La₃Zr₂O₁₂固体氧化物电解质的体积Li⁺迁移率提高了600%。利用表面Li⁺导电，制备了一种超轻氧化物气凝胶固态电解质，其密度为0.29g·cm^-3，仅为液体电解质的25%和石榴石型固体电解质的5.7%。在相同的电解质厚度下，LiFePO4固态电池的能量密度高达295Wh·kg^-1，达到了Li₇La₃Zr₂O₁₂固态电池的160%。

此外，这一设计表面导电超离子导体的指导方针是通用的，可以扩展到不同的阳离子和衬底，有前景的轻质、高导电性的固态电解质，具有广泛的意义，超出了固态电池。

据了解，大块锂离子导电锂超离子导体容易受到晶界和颗粒间孔隙度的破坏，因此需要高密度化，从而限制了固态电池的重量能量密度。

附：英文原文

Title: Surface-Conducting Lithium Superionic Conductors for Solid-State Batteries

Author: Bing Ai, Wenru Zhao, Malin Li, Wei Zhang, Donghai Mei, Jihong Yu

Issue&Volume: March 24, 2025

Abstract: Bulk Li+-conducting lithium superionic conductors are susceptible to disruption by grain boundaries and interparticle porosity, necessitating high densification and consequently limiting the gravimetric energy density of solid-state batteries. Here, we discovered a new class of surface-conducting lithium superionic conductors achieved through surface chemisorption. After bonding with ligands, surface atoms of inert substrates become binding sites for lithium salt dissociation and hopping sites for fast surface Li+ diffusion, transforming inert materials into surface-conducting Li+ conductors. Using two-dimensional TiO2 nanosheets as a proof of concept, we show that ethylene glycolate-chemisorbed TiO2 significantly enhances lithium salt dissociation and promotes fast Li+ hopping between surface oxygen atoms, achieving a high surface ion mobility of 3.61 × 10–7 cm2·V–1·s–1─an improvement of 600% over the bulk Li+ mobility of Li7La3Zr2O12 solid oxide electrolytes. Benefiting from surface Li+ conduction, an ultralight oxide aerogel solid-state electrolyte was developed with an unprecedented low density of 0.29 g·cm–3, which is only 25% of that of liquid electrolytes and 5.7% of garnet-type solid electrolytes. A LiFePO4-based solid-state battery utilizing this new electrolyte exhibits a significantly high energy density of ～295 Wh·kg–1, achieving 160% of that of a Li7La3Zr2O12-based solid-state battery even with the same electrolyte thickness. Furthermore, this guideline for designing surface-conducting superionic conductors is generalizable and can be extended to diverse cations and substrates, promising lightweight, highly conductive solid-state electrolytes with broad implications beyond solid-state batteries.

DOI: 10.1021/jacs.4c16447

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c16447