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Ethyl acetate (EA) was identified as a promising electrolyte solvent for sodium-ion batteries (SIBs), exhibiting low viscosity, cost-effectiveness, and low toxicity. Despite a significant portion of aggregation being linked to the weak solvation of Na+/EA as revealed by molecular dynamics (MD) simulations, pulsed-field gradient nuclear magnetic resonance (pfg-NMR) analysis identified a noteworthy Na+ diffusion coefficient of 3.95×10−10 m2 s−1 at 25°C in the presence of 1 m NaPF 6 salt. Employing fluoroethylene carbonate (FEC) as a film-forming additive to create electrode-electrolyte interphase, this electrolyte surprisingly made ∼210 mAh Na 0.97 Ca 0.03 [Mn 0.39 Fe 0.31 Ni 0.22 Zn 0.08 ]O 2 (NCMFNZO)/hard carbon (HC) pouch cells achieve a lengthy cycling lifetime of 250 cycles with ∼80 % capacity retention, cycled up to 4.0 V at 40°C. X-ray photoelectron spectroscopy (XPS) revealed increasing interphasial organic species over cycling, augmenting charge transfer resistance on both cathode and anode, particularly during fast charging or low temperatures (<10°C), promoting Na plating. Gas chromatography-mass spectrometry combined with density functional theory identified CO 2 as the major gas generated from charged cathode/electrolyte interactions, exhibiting temperature/voltage dependence. [Display omitted] • Developed a new ethyl acetate-based non-aqueous electrolyte for sodium ion batteries. • Revealed the unique bulk structure of electrolyte with weakly solvating characteristics. • Demonstrated extended lifetime for Na 0.97 Ca 0.03 [Mn 0.39 Fe 0.31 Ni 0.22 Zn 0.08 ]O 2 /hard carbon pouch cells up to 4.0 V at 40°C • Identified cell failure mechanisms including impedance growth, sodium plating, gas evolution, and thermal instability [ABSTRACT FROM AUTHOR]

In a lithium‐ion battery, the organic solvent in the electrolyte simply acts as a medium that facilitates ionic charge transfer, whereas for the lithium‐sulfur (Li—S) battery, the choice of the electrolyte is critical as it influences the chemical nature of the soluble polysulfides and the cycling stability of the lithium metal anode. Li‐S batteries currently use ether‐based electrolytes with high polysulfide solubility. Until now, however, the necessary requirements and the roles of the electrolytes have been inconclusive. This work elucidates the essential features and functions of the electrolyte based on an intensive investigation into 17 variants of solvents. Furthermore, examples of electrolytes for high performance, rechargeable Li—S batteries are suggested. The three major study procedures are (1) analyzing the chemical stability of reactive polysulfide species and lithium metal in the solvents of choice, (2) inspecting the chemical reactivity of lithium metal in a polysulfide solution, and (3) evaluating the influences of the solvent on the performance of Li—S cells. Based on the chemical and electrochemical test results, we suggest that the stability of the active materials (i.e., lithium metal and lithium polysulfides) should be ensured in an electrolyte for the proper operation of Li—S cells, that chemical reactions between the polysulfide species and lithium metal should be negligible during the charge–discharge process. In addition, we have confirmed that the high polysulfide solubility is essential for high rate performance. [ABSTRACT FROM AUTHOR]

Abstract CN(CH 2) 2 Si(CH 3)(OCH 2 CH 2 OCH 3) 2 (BNS) is used as electrolyte solvent to improve the safety for LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM)/graphite battery. BNS increases the thermal stability of the carbonate-based electrolyte with (de) lithiated cathode/anode and the electrochemical stability of coin cells. By using an optimal BNS-based electrolyte formula, 13 Ah NCM/graphite prismatic cell achieves 95.8% retain of capacity at 2 C/3 C (charge/discharge) rate after 600 cycles. Meanwhile, 13 Ah prismatic cell exhibits improved safety performance in the nail penetration test. [ABSTRACT FROM AUTHOR]

Abstract: High oxygen radical stability of electrolyte solvent is a key parameter necessary to overcome a large voltage gap in discharge–charge profiles of the non-aqueous Li–air battery. We have proposed N-methyl-N-propylpiperidinium bis(trifluoromethansulfonyl)amide (PP13TFSA) as an appropriate candidate of the electrolyte solvent. PP13TFSA based Li–O2 cells enabled us to draw low charging voltage of around 3.3 V, lowering the voltage gap by nearly half in comparison with those of conventional carbonate-based cells (c.a. 1.4 V). Here, through the detailed analyses of discharge products, we verified the fact that the voltage gap was notably decreased by using the highly radical stable electrolyte solvent. TEM-EELS and FT-IR analyses indicated that Li2O2 was deposited as a discharge product. 13C NMR spectroscopy suggested that no decomposed species derived from electrolyte decomposition was observed from a discharged cathode. GC–MS analyses also revealed that CO and CO2 gases as indices of the decomposed species were not monitored at all. Above-described data substantiated a desirable discharge reaction, resulting in low charging voltage as well as small voltage gap. Design of electrolyte solvents based on their oxygen radical stability and full understanding of the cathode reaction mechanism contributed greatly to a dramatic improvement of the Li–air battery performances. [Copyright &y& Elsevier]

Abstract: A new fire-retardant—dimethyl(2-methoxyethoxy)methylphosphonate (DMMEMP) has been synthesized and evaluated as a high safe electrolyte solvent for lithium-ion batteries. This report summarizes the physical and electrochemical properties of the new compound. It is found that, this nonflammable phosphonate has a moderate viscosity, a high dielectric constant and a good thermal stability. It can provide a wide electrochemical stability window of 0–5.5V (vs. Li+/Li), a high conductivity of 2.0mScm−1 at 20°C with 1M LiTFSI. The electrochemical performance investigated with the Li/LiFePO4 half-cells shows a good capacity of 148.1mAhg−1 and a coulombic efficiency close to 100% at the 10th cycle. [Copyright &y& Elsevier]

Abstract: A new fire retardant-dimethyl methyl phosphate (DMMP) was tested as a nonflammable electrolyte solvent for Li-ion batteries. It is found that in the addition of chloro-ethylene carbonate (Cl-EC) as an electrolyte additive, the electrochemical reduction of DMMP molecules can be completely suppressed and the graphite anode can be cycled very well with high initial columbic efficiency (∼84%) and excellent cycling stability in the DMMP electrolyte. The prismatic C/LiCoO2 batteries using 1.0molL−1 LiClO4 +10% Cl-EC+DMMP electrolyte exhibited almost the same charge and discharge performances as those using conventional carbonate electrolytes, suggesting a feasible use of this new electrolyte for constructing nonflammable Li+-ion batteries. [Copyright &y& Elsevier]

Abstract: Dimethyl methyl phosphonate (DMMP) was selected and tested as a non-flammable solvent for primary and secondary lithium batteries, because of its non-flammability, good solvency of lithium salts and appropriate liquidus properties. Experimental results demonstrated that DMMP can solvate considerable amount of commonly used lithium salts to form non-flammable and Li+-conducting electrolyte, which has very wide electrochemical window (>5V vs. Li) and excellent electrochemical compatibility with metallic lithium anode and oxide cathodes. Primary Li–MnO2 cells using DMMP-based electrolyte showed almost the same discharge performances as those using organic carbonate electrolytes, and also, Li–LiMn2O4 cells using DMMP electrolyte exhibited greatly improved cycleability and dischargeability, suggesting a feasible application of this new electrolyte for constructing high performance and non-flammable lithium batteries. [Copyright &y& Elsevier]

Abstract: Novel silane compounds such as {2-[2-(2-methoxyethoxy)ethoxy]ethoxy} trimethylsilane (1), bis{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}dimethylsilane (2), {3-[2-(2-(2-methoxyethoxy)ethoxy)ethoxy]-propyl}trimethylsilane (3) and {[2-(2-(2-methoxyethoxy)ethoxy)ethoxy]-methyl} trimethylsilane (4) have been synthesized and used as non-aqueous electrolyte solvents in lithium-ion batteries. These silane molecules can easily dissolve most lithium salts including lithium bis(oxalato)borate (LiBOB), LiPF6, LiBF4, and lithium trifluoromethylsulfonimide. The LiBOB salt was found to be very appropriate for these silane molecules because, unlike LiPF6, LiBOB can provide a good passivation film on a graphite anode. Cyclic voltammetry analyses show that silane-based electrolytes with a 0.8M LiBOB salt concentration are stable to 4.4V; they also exhibit very high lithium-ion conductivities up to 1.29×10−3 S/cm at room temperature. Full cell performance tests with LiNi0.08Co0.15Al0.05O2 as the positive electrode and MCMB graphite as the negative electrode have shown excellent cyclability both at room temperature and at 40°C. Cells with these new silane electrolytes exhibit long calendar life; they show no impedance rise after aging at 80% state of charge and 55°C for one year. The results suggest that silane-based electrolytes have great potential for use in lithium-ion batteries. [Copyright &y& Elsevier]

Significant progress has been made to replace graphite anode materials with Li metal in next-generation Li ion batteries, called Li metal batteries (LMBs). However, the development of practical LMBs requires the suppression of Li dendrites. Owing to their ability to relax polarization, single-ion solid polymer electrolytes (SSPEs) are widely considered as an effective strategy for preventing dendrite generation. The novel SSPE membrane prepared in this work, which consists of a polymeric lithium salt modified with an electrolyte solvent, shows single-ion conducting behavior that results in the effective restriction of Li dendritic growth. The SSPE membrane delivers an ionic conductivity as high as 1.42 × 10 -4 S cm -1 at room temperature. A LiFePO 4 (LFP) coin cell assembled with the SSPE membrane shows excellent rate performance and outstanding cycling stability. In addition, the LFP flexible battery using the SSPE membrane exhibits good practicability and environmental adaptability.