An Additive Study for Water-in-Salt Electrolyte (WiSE) with Lithium Manganese Oxide (LMO) and Titanium Niobate (TNO) Electrodes
Abstract
Aqueous electrolytes are poised to eliminate numerous safety concerns relative to state-of-the-art organic electrolytes; however, they continue to suffer from parasitic side reactions that consume lithium and limit performance. In this study we performed additive screening of 10 species for water-in-salt electrolytes (WiSEs) with the goal of forming a more robust and resilient anode solid-electrolyte interphase against hydrogen evolution at the anode. Coin cells consisted of a high-loading LiMnO2 cathode (13.32 mg cm-2) and a low-loading TiNb2O7 anode (3.32 mg cm-2) to isolate the impact on anode performance. Down-selections were performed over the course of four experiments including 1) solubility, 2) impedance, 3) cycling retention, and 4) storage, with the baseline WiSE electrolyte outperforming all other WiSE-plus-additive compositions. However, the baseline WiSE electrolyte also suffered a 37 percent drop in energy density relative to similar cells with conventional organic electrolyte (1.0 M LiPF6 in ethylene carbonate:diethyl carbonate [EC:DEC]). Storage tests proved particularly useful for determining the amount of parasitic current at certain cell potentials (2.3, 2.4, and 2.5 V), which correlates to coulombic inefficiency. These results indicate a pressing need to reduce parasitic reactions at the anode by investigating protective coatings and less-catalytic anode materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2022
- Accession Number
- AD1189023
Entities
People
- Arthur Von Cresce
- Brett Sweeney
- Glenn Pastel
- Jackson Carter
- Janet Sun
- Marshall A Schroeder
- Matthew Sieh
Organizations
- United States Army Research Laboratory