Li-ion hopping conduction in highly concentrated lithium bis(fluorosulfonyl)amide/dinitrile liquid electrolytes

Abstract

Li+ ion hopping conduction through ligand (solvent and anion) exchange emerges in solvent-deficient liquid electrolytes of [Li salt]/[dinitrile] > 1.

Concentrated Ionic‐Liquid‐Based Electrolytes for High‐Voltage Lithium Batteries with Improved Performance at Room Temperature

“…However, the formation of aggregate species seems to have a rather different influence on the transport of Li + ions. It has been proposed that, in a concentrated electrolyte, the Li + transport mechanism changes from a diffusion‐controlled vehicular transport of small Li + complexes to hopping‐type ion transport through the exchange of anions in the Li + ‐containing aggregate species . This must be true to explain the exceptional performance of the Li/LMR cell employing the DEMEFTFSI 0.6 LiFTFSI 0.4 at high rates, despite its substantially lower conductivity and higher viscosity than the electrolytes containing 10 and 20 mol % LiFTSFI.…”

Enhanced Cycling Performance of Ni-Rich Positive Electrodes (NMC) in Li-Ion Batteries by Reducing Electrolyte Free-Solvent Activity

“…Here we examine this oxide-mediated electrolyte oxidation mechanism 14,16,17,37,58 by employing highly concentrated carbonate-based electrolytes and electrolyte salts of different dissociation constants, and test if having fewer free carbonate molecules can potentially reduce the electrolyte reactivity with Ni-rich NMC. Highly concentrated electrolytes that typically have a salt molar concentration greater than ~3 M and a molar ratio of Li:solvent less than 1:4, have shown radically different properties such as reduced volatility/flammability 55,[59][60][61][62][63][64] , greater electrochemical stability window [65][66][67][68][69] , enhanced rate performance 56,68,[70][71][72] , and altered interfacial reactivity 61,[66][67][68]70,[73][74][75][76][77][78][79] from conventional electrolytes (~1 M). 13,80 These changes have been attributed to the reduction of free solvent molecules that do not coordinate with Li ions 62,[81][82][83] .…”

Recent Developments of Nanomaterials and Nanostructures for High‐Rate Lithium Ion Batteries

“…The hopping of lithium ion is prevalent in solid-state diffusion, which is influenced by a myriad of factors, including crystal structure of the matrix material, presence of defects, chemical and physical properties of the diffusing components. [52] According to transition state theory, the probability (Γ) of a hopping case for an atom or ion can be estimated by Equation (8). [53]…”