Methyl Carbamate‐Lithium Salt Deep Eutectic Electrolyte for Lithium‐Ion Batteries

Abstract

Deep eutectic electrolytes (DEEs) represent a burgeoning field in electrolytes for energy storage applications. Compared to the more conventionally studied Li‐ion electrolyte systems, these electrolytes offer numerous advantages, such as high ion concentration, costs, lower temperature operation, and safety. In this work, the formation of a novel eutectic electrolyte based on lithium salts and methyl carbamate was reported. These DEEs were formed via mixing lithium salts and low‐cost methyl carbamate at ratios varying from 1 : 2 to 1 : 5 (mol:mol). The DEE formed from methyl carbamate and lithium hexafluorophosphate (LiPF6) at a 1 : 5 molar ratio generated a 4V stability window and a 25 °C conductivity of up to 3.16E−3 S cm−1. The DEE formed from methyl carbamate and lithium bis(trifluoromethane)sulfonimide (LiTFSI) at a 1 : 5 molar ratio generated a 3.2 V stability window and a 25 °C conductivity of up to 2.87E−3 S cm−1. The LiPF6 DEE also demonstrated a discharge capacity of 128 mAh g−1after 50 cycles with 93 % discharge capacity retention at moderate cycling rates of 0.5C in a lithium titanate (LTO)/lithium iron phosphate (LFP) full cell. These results demonstrate the potential for methyl carbamate to generate eutectics from lithium salts and offer alternative electrolytes for use in low‐temperature Li‐ion battery applications.

Suppressing the Shuttle Effect of Aqueous Zinc–Iodine Batteries: Progress and Prospects

“…A eutectic electrolyte is an analog with the electrochemical properties of ionic liquids and with the advantages of good electrical conductivity, excellent electrochemical stability, wide temperature range, simple preparation, and low cost [124][125][126][127][128]. As a new type of electrolyte system, eutectic electrolytes have attracted widespread attention in the field of energy storage [128].…”

Opportunity for eutectic mixtures in metal-ion batteries

“…For example, LiTFSI-MAc and LiNO3-MAc eutectic mixtures show ESWs of 5.3 and 4.7 V (vs. Li), respectively (passivated Al collector) [30]. LiTFSI-Methyl carbamate and LiPF6-Methyl carbamate eutectic mixtures at 1:5 molar ratios give an ESW of 3.2 and 4 V, respectively [43]. The 3.5 V-window Li4Ti5O12//LiMn2O4 full cell rendered by the methylsulfonylmethane (MSM)-lithium perchlorate-water (MSM/LiClO4/H2O) eutectic mixture [44] was explained that all water molecules participate in constructing primary solvation sheath, leading to a weakened activity of water and increased overpotentials of hydrogen/oxygen evolution.…”