Controlling Intermolecular Interaction and Interphase Chemistry Enabled Sustainable Water-tolerance LiMn₂ O₄ ||Li₄...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous Li-ion batteries offer high energy density but are limited by a narrow electrochemical stability window.
• Water-in-Salt electrolytes (WiSE) expand this window but require further stabilization for practical applications.

Purpose of the Study:

• To enhance the cathodic stability of WiSE by introducing trimethyl phosphate (TMP).
• To improve the performance and durability of aqueous Li-ion batteries.

Main Methods:

• Introduction of TMP into WiSE to modify intermolecular interactions and interphase chemistry.
• Investigation of TMP's effect on water activity and SEI formation.
• Assembly and testing of LiMn2O4 (LMO)||Li4Ti5O12 (LTO) full cells.

Main Results:

• TMP effectively limits water activity through strong interactions.
• Reinforced SEI formation involving phosphate and LiF was observed, attributed to manipulated Li+ solvation structure.
• The LMO||LTO full cell demonstrated a long cycling life of 1000 cycles with >99.9% coulombic efficiency.

Conclusions:

• TMP is a promising additive for enhancing the stability and performance of aqueous Li-ion batteries.
• This approach facilitates cost-effective manufacturing of LMO||LTO cells, reducing the need for stringent moisture-free conditions.