Electrolyte Therapy for Improving the Performance of LiNi_0.5Mn_1.5O₄ Cathodes Assembled Lithium–Ion Batteries

Abstract

High voltage spinel manganese oxide LiNi0.5Mn1.5O4 (LNMO) cathodes are promising for practical applications owing to several strengths including high working voltages, excellent operating safety, low costs, and so on. However, LNMO-based lithium–ion batteries (LIBs) fade rapidly mainly owing to unqualified electrolytes, hence becoming a big obstacle toward practical applications. To tackle this roadblock, substantial progress has been made thus far, and yet challenges still remain, while rare reviews have systematically discussed the status quo and future development of electrolyte optimization coupling with LNMO cathodes. Here, we discuss cycling degradation mechanisms at the cathode/electrolyte interface and ideal requirements of electrolytes for LNMO cathode-equipped LIBs, as well as review the recent advance of electrolyte optimization for LNMO cathode-equipped LIBs in detail. And then, the perspectives regarding the future research opportunities in developing state-of-the-art electrolytes are also presented. The authors hope to shed light on the rational optimization of advanced organic electrolytes in order to boost the large-scale practical applications of high voltage LNMO cathode-based LIBs.

A Perspective on the Sustainability of Cathode Materials used in Lithium‐Ion Batteries

“…[36] In order to compete with commercial cobalt-containing cathode materials, methods to improve such failure mechanisms are under investigation. These methods include various doping strategies, [37,38] high-voltage electrolytes, [39,40] surface coatings [41] and particle morphology optimization. [42] Doping with abundant elements, such as iron at low concentrations, has not only shown to improve electrochemical performance, (particularly at high C rates) but could alleviate nickel demand which may prove beneficial when considering long-term supply versus demand (see supply vs demand section).…”

Ordered LiNi0.5Mn1.5O4 Cathode in Bis(fluorosulfonyl)imide-Based Ionic Liquid Electrolyte: Importance of the Cathode–Electrolyte Interphase

“…[4,5] However, the high working potential of LNMO is a double-edged sword: if on one hand it provides high energy and power density, on the other it means dealing with the instability of carbonate-based organic electrolytes at potentials above 4.5 V vs. Li + /Li. [6][7][8][9] At the high cutoff voltage of 5 V, traditional electrolytes containing organic carbonates and LiPF 6 readily decompose to form various by-products such as oxocarbons (CO and CO 2 ) and acidic species, which not only hinder the formation of a stable cathode-electrolyte interphase (CEI) layer, but also cause the dissolution of the transition metals, ultimately leading to poor cycling performance. [10][11][12][13] To mitigate the parasitic reaction between the liquid electrolyte and LNMO surface at high cutoff potential, surface coatings of conductive polymers [14][15][16], oxides [17][18][19], and fluorides [20][21][22] have proven an effective strategy to improve cyclability and therefore extensively investigated.…”

The Importance of Interphases in Energy Storage Devices: Methods and Strategies to Investigate and Control Interfacial Processes

“…The proposed shells are usually made by ZnO, TiO 2 , or Al 2 O 3 as nano-shells formed by chemical selfassembling [154] or ALD [155,156]. From the other part, a better design of the electrolytes can also enable the reversible operation of high voltage-spinel [157]. CEI-forming additives include: (i) phosphorous based compounds like (trimethylsilyl)phosphate [158], which exhibit higher HOMO energy and thus higher decomposition potentials, (ii) carbonyl molecules, like quercetin [159]; (iii) nitrile containing systems [160]), or different lithium salts and lithium borates [161,162].…”