北京理工大学陈人杰小组近日取得一项新成果。他们通过使用小配体溶剂化电解质实现快速充电的水性电池。相关论文于2025年1月14日发表在《德国应用化学》杂志上。

据了解，水分子之间的氢键网络通过跳跃机制实现H⁺和OH^-的超快速扩散，使水电池成为下一代快速充电储能的有力竞争者。广泛应用于锂离子电池的理想水电解质应希望具有宽的电化学稳定窗口（>5伏）、快速充电（≤15分钟）、无气体释放和低成本。然而，水的析氢反应（HER）的窄电压窗（1.23 V）限制了它们的实际应用。

该研究建立了利用低结合能的位阻基团设计小配体电解质的新思路。共用溶剂正碳酸四乙酯（TEOC）具有大尺寸的乙氧基和氢键捕获能力，迫使游离的H₂O和阴离子TFSI^-进入Li⁺第一溶剂化壳层。因此，对水的析氢反应（HER）的抑制是通过固定H₂O活性和在TEOC和H₂O之间形成氢键网络-C-O···H来实现的。

这种独特的结构具有超小的鞘体积，从而促进了富LiF SEI的形成和快速离子传导。在TEOC/H₂O电解质中，双(三氟甲烷磺酰)亚胺锂（LiTFSI）表现出5.7 V的宽电化学窗口，使LiMn₂O₄/Li₄Ti₅O₁₂袋状电池在10℃的快速速率下达到1200次循环。这种微小配体溶剂化工程为开发平衡性能和可持续性的高级电解质开辟了新的途径。

附：英文原文

Title: Tiny-Ligand Solvation Electrolyte Enabled Fast-charging Aqueous Batteries

Author: Yanxin Shang, Nan Chen, Yuejiao Li, Shi Chen, Zhujie Li, Shengxi Li, Xuening Ren, Yusheng Ye, Li Li, Feng Wu, Renjie Chen

Issue&Volume: 2025-01-14

Abstract: The H-bond network among H2O molecules enables ultrafast diffusion of H+ and OH- via a hopping mechanism, making aqueous batteries attractive competitors for next-generation fast-charging energy storages. Ideal aqueous electrolyte for the widely used lithium-ion batteries is expected to have the wide electrochemical stability window (>5 volts), fast charging (≤15 minutes) without gas evolution, and low cost. However, the hydrogen evolution reaction (HER) associated with narrow voltage window of water (1.23 V) limits their practical applications. Herein, we built a new guideline for designing tiny-ligand electrolytes by utilizing sterically hindered groups with low binding energy. Cosolvent tetraethyl orthocarbonate (TEOC), with large-sized ethoxy groups and hydrogen-bond-captured ability, forces free H2O and anion TFSI- into the Li+ first solvation shell. Hence, inhibition of HER takes place by means of immobilized H2O activity and formation of hydrogen-bonding networks—C-O···H between TEOC and H2O. This unique structure with ultra-small sheath volume thereby facilitates the formation of LiF-rich SEI and fast ion-conduction. The lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in TEOC/H2O electrolyte exhibits wide electrochemical window of 5.7 V, enabling LiMn2O4/Li4Ti5O12 pouch cells to achieve 1200 cycles under rapid 10 C rate. This engineering of tiny-ligand solvation opens new pathways for developing advanced electrolyte that balance performance with sustainability.

DOI: 10.1002/anie.202423808

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202423808