Recent advances in the electrolytes for interfacial stability of high-voltage cathodes in lithium-ion batteries

Abstract

More oxidative than carbonate solvents such as EC Oxidative additive with high HOMO energy HOMO energy of carbonate solvents such as EC e -Stable SEI layer Energy HOMO energy of high-voltage solvents such as sulfone, fluorinated solvents Highly stable electrolytes at high voltages (without the SEI formation on the cathode) Search for high-voltage electrolytes using HOMO energy calculation Possible candidates by theoretical molecular orbital calculation Screening oxidative additives or high-voltage solvents using electrochemical floating test and LSV/CV Finding the optimized electrolytes for high-voltage cathodes through electrochemical test of cellsWe present the useful processes in the research of functional electrolytes for interfacial stability of high-voltage cathodes in Li-ion batteries.Advanced electrolytes with unique functions such as in-situ formation of a stable artificial solid electrolyte interphase (SEI) layer on the anode and the cathode, and the improvement in oxidation stability of the electrolyte have recently gained recognition as a promising means for highly reliable lithium-ion batteries with high energy density. In this review, we describe several challenges of the cathode (spinel lithium manganese oxide (LMO), lithium cobalt oxide (LCO), lithium nickel cobalt manganese oxide (NCM), spinel lithium manganese nickel oxide (LNMO), and lithium-rich layered oxide (Li-rich cathode))-electrolyte interfaces and highlight the recent 10 progress in the use of oxidative additives and high-voltage solvents in high-performance cells. 75 solvents with high anodic stability, researchers have also investigated the use of functional oxidative additives to modify the surface chemistry of the cathode and attain high-performance cathodes for use in LIBs. [25][26][27] In this review, we present the problematic issues regarding 80

Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

“…103,104 Strategies to improve the surface properties include doping, 105 surface coatings, 106,107 and electrolyte additives. 108 These approaches typically result in trade-offs of maximum specific capacity and first cycle coulombic efficiency 109 for decreased impedance rise, thermal stability, and reduced CEI buildup to increase cell-cycle life. 110 One especially promising approach to reduce surface reactivity and prolong the cycle life of Nirich NMCs is the development of compositionally graded cathodes with less Ni at the surface.…”

Lithium Bis(2,2,2-trifluoroethyl)phosphate Li[O2P(OCH2CF3)2]: A High Voltage Additive for LNMO/Graphite Cells

“…[18][19][20] The usefulness of P-based additives for HV applications has been recently reported. 11,21,22 2 ], also referred to as LiBFEP; see E in Scheme 1) has been used as a coordinationpolymer-based gel electrolyte in our recent work. 32 LiBFEP forms a viscous gel in EC/DMC (1/1 g:g) at 0.5 M with a rather low conductivity of 41.8 μS·cm −1 at room temperature.…”

“…The oxidative instability of carbonate-based electrolytes is a central limitation for cells with various cathode chemistries operated above 4.4 V. [3][4][5][6][7] In addition to the instability of the electrolyte, cathodes such as nickel-rich layered oxides (LiNi x Mn y Co z O 2 ), lithium-rich layered oxides (0.6 Li 2 MnO 3 • 0.4 Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 ), and HV spinel (LiNi 0.5 Mn 1.5 O 4 ) (LNMO) all suffer from structural instability when operated at high potentials. [5][6][7][8][9][10][11] While the layered oxides are capable of delivering higher practical energy densities, the lack of cobalt in LNMO alleviates the issues of cost and resource limitations. 7 As the higher energy densities associated with HE materials can only be obtained at higher cutoff potentials, oxidation of the electrolyte is a universal problem to both HE and HV cathodes.…”

Electrolyte-cathode interactions in 5-V lithium-ion cells

“…The HF leads to Mn and Ni dissolution [10]. Certain electrolytes and their additives have been found to enhance the stability of the high-voltage cathode materials; however, compared to anodes, the reactions between the cathode and the electrolyte have not been explained in great detail so far [12][13][14].…”