A new class of Solvent-in-Salt electrolyte for high-energy rechargeable metallic lithium batteries

Abstract

Liquid electrolyte plays a key role in commercial lithium-ion batteries to allow conduction of lithium-ion between cathode and anode. Traditionally, taking into account the ionic conductivity, viscosity and dissolubility of lithium salt, the salt concentration in liquid electrolytes is typically less than 1.2 mol l À 1 . Here we show a new class of 'Solvent-in-Salt' electrolyte with ultrahigh salt concentration and high lithium-ion transference number (0.73), in which salt holds a dominant position in the lithium-ion transport system. It remarkably enhances cyclic and safety performance of next-generation high-energy rechargeable lithium batteries via an effective suppression of lithium dendrite growth and shape change in the metallic lithium anode. Moreover, when used in lithium-sulphur battery, the advantage of this electrolyte is further demonstrated that lithium polysulphide dissolution is inhibited, thus overcoming one of today's most challenging technological hurdles, the 'polysulphide shuttle phenomenon'. Consequently, a coulombic efficiency nearing 100% and long cycling stability are achieved.

Research Progress towards Understanding the Unique Interfaces between Concentrated Electrolytes and Electrodes for Energy Storage Applications

“…In the electrolyte modulation approaches, the use of concentrated electrolyte is an effective strategy to restrain the dissolution of polysulfides in the electrolyte and alleviate the ‘sulfur shuttle’ reactions, thus improving the long‐term cycle life of Li–S batteries 15, 53. Suo et al proposed a class of solvent‐in‐salt electrolytes with LiTFSI concentrations up to 7 mol L −1 of DOL‐DME, which can effectively inhibit the dissolution of lithium polysulfides and also mitigate the Li metal corrosion 15.…”

MoS2‐Based Nanocomposites for Electrochemical Energy Storage

“…Moreover, it can store the non‐continuous energy harvesting from other alternative clean energies (wind energy, solar energy, and hydroenergy) as chemical energy and release it as electric energy to power various devices when needed 44. In this field, Goodenough, Tarascon, J. Dahn, L. Chen, and Zhao et al have carried out intensive investigations on new‐types of cathodes and have made meaningful discoveries on the lithiation/delithiation mechanisms as well as anodes with high capacities and stable cycling performances 45, 46, 47, 48, 49, 50, 51, 52. Nowadays, Li‐ion batteries are widely used in portable electric devices and electric vehicles with high energy density, thus reducing the consumption to fossil fuel in some degree 53, 54.…”

Passivation of Lithium Metal Anode via Hybrid Ionic Liquid Electrolyte toward Stable Li Plating/Stripping

“…However, these strategies cannot change the breakage/repair mechanism of SEI layer, and significantly improve the Coulombic efficiency of Li plating/stripping. In addition, optimization of electrolyte using additives,8 high concentrated electrolytes,9 and ionic liquid electrolytes10 can enhance the stability of SEI layers, and can improve the Coulombic efficiency of Li plating/stripping. However, the electrolyte additives are consumed during the SEI formation and thus affect the electrochemical performance.…”