Electrolyte Additives for Room‐Temperature, Sodium‐Based, Rechargeable Batteries

Abstract

Owing to resource abundance, and hence, a reduction in cost, wider global distribution, environmental benignity, and sustainability, sodium-based, rechargeable batteries are believed to be the most feasible and enthralling energy-storage devices. Accordingly, they have recently attracted attention from both the scientific and industrial communities. However, to compete with and exceed dominating lithium-ion technologies, breakthrough research is urgently needed. Among all non-electrode components of the sodium-based battery system, the electrolyte is considered to be the most critical element, and its tailored design and formulation is of top priority. The incorporation of a small dose of foreign molecules, called additives, brings vast, salient benefits to the electrolytes. Thus, this review presents progress in electrolyte additives for room-temperature, sodium-based, rechargeable batteries, by enlisting sodium-ion, Na-O /air, Na-S, and sodium-intercalated cathode type-based batteries.

Confronting the Challenges of Next‐Generation Silicon Anode‐Based Lithium‐Ion Batteries: Role of Designer Electrolyte Additives and Polymeric Binders

“…The incorporation of a small amount of foreign species, called functional additives, is hailed as one of the most viable, economical, and effective strategies for circumventing the massive volume changes and initial capacity loss due to continuous electrolyte decomposition in high capacity and reactive electrode materials, such as Li metal (Li 0 ), Si, and Na . Reducible and oxidizable electrolyte additives are expected to modify the SEI and cathode–electrolyte (CEI) interphases, respectively; thus altering and tuning their composition and accompanying properties.…”

Nonaqueous Sodium‐Ion Full Cells: Status, Strategies, and Prospects

“…High ionic conductivity, wide operating voltage window, good thermal stability, environmental friendliness, and low cost are the most basic requirements that all electrolytes need to meet in practical applications. Much work on electrolytes has been systematically studied by many researchers and provides guidance for the rational selection of electrolytes . Here, combined with their applications in the full cell, we try to pick out the preferred electrolytes in these diverse systems.…”

“…From the most basic concept, to ensure the stability of the cell the energy levels of the cathode and anode materials should be lower and higher than the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) levels of the electrolyte, respectively ( Figure a). However, since lower voltage anodes and higher voltage cathodes are often employed to develop cells with higher energy density and power density, the formation of interfacial films or the occurrence of side reactions are also inevitable . Generally, nonaqueous liquid electrolytes can be grouped into three broad categories: esters, ethers, and ionic liquids.…”

“…Φ A and Φ C are the anode and cathode work functions, respectively, E g is the window of the electrolyte for thermodynamic stability. Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…The ideal film‐forming additive needs to have a lower LUMO level and a higher HOMO level than solvents, electrolyte salts, etc., which helps them to decompose in preference to solvents, electrolyte salts, etc., thereby improving the film‐forming quality of the interface film (Figure a). Such additives currently reported mainly include FEC, tris(trimethylsilyl) phosphate (TMSP), vinyl carbonate (VC), RbPF 6 , and CsPF 6 , etc., however, the additives used in the full cells are almost all FEC because it has universal compatibility and modification for both cathode and anode. When used as an additive, FEC can induce the formation of a thin and dense interface film to prevent the erosion of electrolyte to electrode accompanied by the formation of products such as alkyl compounds, NaF, and Na 2 CO 3 ( Figure a) .…”