Design aspects of electrolytes for fast charge of Li‐ion batteries

Abstract

The electrolytes of Li-ion batteries consist mainly of a LiPF 6 salt dissolved in a carbonate-based solvent mixture. Such electrolytes cannot support fast charge without detrimental impacts on performance and lifetime. Fast charge aggravates parasitic reactions of the electrolyte solvents and structural degradation of the lithium layered transition metal oxide cathode materials. This leads to not only the depletion of electrolyte solvents but also the loss of cyclable Li + ions, accompanied by impedance growth and volumetric swelling of the battery. In this perspective, the design aspects of the electrolytes for fast charge of Li-ion batteries are discussed and proposed.

Mechanistic Insights of Mg2+‐Electrolyte Additive for High‐Energy and Long‐Life Zinc‐Ion Hybrid Capacitors

“…Due to the incomplete desolvation of Zn(H 2 O) 6 2+ , bare Zn suffers from the interface side reactions and hydrogen evolution of water molecules (Figure S23, Supporting Information). [ 44–46 ] CV curves with and without Mg 2+ additive in three‐electrode cell also verify the inhibition of hydrogen evolution (Figure S24, Supporting Information). The formation of Zn dendrites during cycling can be described as a “tip effect,” [ 47,48 ] that the elevated tip electric field aggravates the growth of Zn dendrite.…”

Ether‐Based Electrolyte Chemistry Towards High‐Voltage and Long‐Life Na‐Ion Full Batteries

“…[7] Hence,the rational design for ether-based electrolyte is ap racticable modification strategy to extend the antioxidative window via reducing dissociative ethers with aggressive reactivity. [11] But to our knowledge,none of appropriate target electrolytes exceeding 4.0 Vi sr eported for Na-ion full cells until now. [12] Herein, by modulating highly coordinated configuration to remarkably suppress solvent activity,wereport amodified ether-based electrolyte by dissolving 3.04 mN aPF 6 in diethylene glycol dimethyl ether (DEGDME) with the addition of 1,3-dioxolane (DOL) diluent (10:1 by volume ratio) which possesses not only highly oxidative stability but also suitability with various anodes.Asaresult, the designed electrolyte withstands high-voltage Na 3 V 2 (PO 4 ) 2 O 2 F( NVPF) cathode up to 4.5 Vaccompanied by robust interphase featuring enriched and uniformly distributed inorganic-rich components.S ubsequently integrated with graphite anode characterized by unique Na + -solvent co-intercalation, the matched Graphite//NVPF full batteries show outstanding rate performance and unprecedented cyclic stability (100 mA hg À1 is maintained at 0.2 Ag À1 even over 1300 cycles,corresponding to acapacity retention of 90 %equivalent to an extremely low capacity decay of about 0.0077 %per cycle), enabling graphite-based Na-ion full cells.T ofurther prove the universality of designed electrolyte with other anodes and boost overall energy density,t he full cells composed of prepared hard carbon anode and NVPF cathode are assembled with 3.72 V average output voltage (corresponding to av ery high energy density of 247 Wh kg À1 based on the total mass of anode/ cathode electrode), all the electrochemical performances outperform that delivered by most batteries employing carbonate-based electrolytes.I naword, this work increases abundance and selective diversity for electrolytes used in Naion full cells,enabling one of the most promising electrolytes for application of NIBs.…”

In Situ/Operando Raman Techniques in Lithium–Sulfur Batteries

“…Besides the challenges on cathode side, Li–S batteries also suffer from uncontrollable growth of lithium dendrite on the anode side, which accelerates the degradation of lithium anode and consumption of electrolyte, causing low Coulombic efficiency and serious safety issues. [ 42,43 ] The main reason for the growth of lithium dendrite can be attributed to the low lithium ion concentration and inhomogeneous lithium ion flux on the surface of anode. [ 44–46 ] During charging, reduction of the lithium ion at electrochemical interface leads to the barren region of lithium ion.…”