Compared with other commercial cathode materials, the LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode (NCM811) has high specific capacity and a relatively low cost. Nevertheless, the higher nickel content in NCM811 leads to an extremely unstable interface between the electrode and the electrolyte, resulting in inferior cyclic stability of the corresponding cell. Use of film-forming additives is regarded as the most feasible and economic approach to construct a stable interface on the NCM811 cathode. However, less effective electrolyte additives have been reported to date. Herein, we propose a valid film-forming electrolyte additive, 2,4,6triphenyl boroxine (TPBX), for application in a high-voltage NCM811 cathode. Experimental and computational results reveal that the TPBX additive can be preferentially oxidized to generate a highly stable and conductive cathode electrolyte interface (CEI) layer on the NCM811 cathode, which efficiently suppresses the detrimental side reaction and improves the electrochemical performance eventually. In detail, the cyclic stability of the Li/NCM811 half-cell is enhanced from 57% (without additive) to 78% (with 5% TPBX) after 200 cycles at 1C between 3.0 and 4.35 V. At a high current rate of 15C, the TPBX-containing electrode delivers a capacity of about 135 mAh g −1 , which is much higher than that of the electrode without the additive (80 mAh g −1 ). Interestingly, the TPBX is also reduced earlier than the ethylene carbonate (EC) solvent to form an ionically conductive solid electrolyte interface (SEI) film on the graphite anode. Due to the CEI layer on the cathode and the SEI film on the anode simultaneously formed by the TPBX additive, the cyclic performance of the graphite/ LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cell is enhanced. Therefore, the incorporation of the TPBX additive into the electrolyte provides a convenient method for the commercial application of the high-energy-density NCM811 cathode in high-voltage lithium-ion batteries. KEYWORDS: LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), electrolyte additive, 2,4,6-triphenyl boroxine, cathode electrolyte interface, high-energy-density lithium-ion battery

Growth in intermittent renewable sources including solar and wind has sparked increasing interest in electrical energy storage. Grid‐scale energy storage integrated with renewable sources has significant advantages in energy regulation and grid security. Aqueous zinc‐ion batteries (AZIBs) have emerged as a practically attractive option for electrical storage because of environmentally benign aqueous‐based electrolytes, high theoretical capacity of Zn anode, and significant global reserves of Zn. However, application of AZIBs at the grid‐scale is restricted by drawbacks in cathode material(s). Herein, a comprehensive summary of the features and storage mechanisms of the latest cathode materials is provided. The fundamental problems and corresponding in‐depth causes for cathode materials is critically reviewed. It is also assess practical challenges, appraise their translation to commerce and industry, and systematically summarize and discuss the potential solutions reported in recent works. It is established necessary design strategies for Zn anodes and electrolytes that are matched with cathode materials for commercializing AZIBs. Finally, it is concluded with a perspective on the practical prospects for advancing the development of future AZIBs. Findings will be of interest and benefit to a range of researchers and manufacturers in the design and application of AZIBs for grid‐scale energy storage.

The non‐flammability and high oxidation stability of sulfolane (SL) make it an excellent electrolyte candidate for lithium‐ion batteries (LIBs). However, its incompatibility with graphitic anode prevents the realization of these advantages. To understand how this incompatibility arises on molecular level so that it can be suppressed, we combined theoretical calculation and experimental characterization and reveal that the primary Li+ solvation sheath in SL is depleted of fluorine source. Upon reduction, SL in such fluorine‐poor solvation sheath generates insoluble dimer with poor electronic insulation, hence leading to slow but sustained parasitic reactions. When fluorine content in Li+‐SL solvation sheath is increased via salt concentration, a high stability LiF‐rich interphase on graphite can be formed. This new understanding of the failure mechanism of graphite in SL‐based electrolyte is of great significance in unlocking many possible electrolyte solvent candidates for the high‐voltage cathode materials for next‐generation LIBs.

Electrolyte additives have been successfully applied for the performance amelioration of lithium-ion batteries, especially under high voltage, which are based on the protective interphases on anode and cathode. Many additives have been proposed but less knowledge is available on the relationship between additive molecule structure and the interphase stability. In this work, we uncover the significance of the additive molecule structure in constructing a stable and robust interphase by comparing the effects of two similar additives, trimethyl borate (TMB) and tripropyl borate (TPB), on the performance of a layered lithiumrich oxide cathode (LRO) under a high voltage (4.8 V). Electrochemical measurements combined with physical characterizations and theoretical calculations demonstrate that TMB and TPB exhibit similar oxidative activity and both can build protective cathode interphases on LRO but they yield different cyclic stability improvement for LRO. The B-containing species derived from the TMB oxidation are more stable, yielding a more robust interphase than those from the TPB oxidation. This established relationship paves a road to design electrolyte additives more efficiently for high-voltage batteries.

Li dendrite growth due to uncontrolled Li plating/stripping processes has been a challenge for the application of Li metal anodes in high energy secondary batteries. A novel strategy is proposed in this work to address this issue, which is based on simultaneously regulating Li ion (Li+) flux and Li metal surface activity by a terpolymer cladding that orients the Li+ flux and mitigates the side reactions for Li plating/striping. This cladding provides the Li anode with dendrite-free surface morphology and enhanced electrochemical performances. Stable cycling of 800 and 1400 h is achieved for Li symmetric cells in carbonate-based and ether-based electrolytes, respectively. In addition, the asymmetric Li–LiFePO4 and Li–sulfur cells attain a prolonged cycle lifespan with reduced interfacial resistance after cycling. These performances might be further improved by more delicately designing the polymer structure and assembling the cladding, which might help fulfill the practical applications of Li anodes in high energy batteries.