Electrolyte Engineering Toward High Performance High Nickel (Ni ≥ 80%) Lithium‐Ion Batteries

Abstract

High nickel (Ni ≥ 80%) lithium‐ion batteries (LIBs) with high specific energy are one of the most important technical routes to resolve the growing endurance anxieties. However, because of their extremely aggressive chemistries, high‐Ni (Ni ≥ 80%) LIBs suffer from poor cycle life and safety performance, which hinder their large‐scale commercial applications. Among varied strategies, electrolyte engineering is very powerful to simultaneously enhance the cycle life and safety of high‐Ni (Ni ≥ 80%) LIBs. In this review, the pivotal challenges faced by high‐Ni oxide cathodes and conventional LiPF6‐carbonate‐based electrolytes are comprehensively summarized. Then, the functional additives design guidelines for LiPF6‐carbonate ‐based electrolytes and the design principles of high voltage resistance/high safety novel electrolytes are systematically elaborated to resolve these pivotal challenges. Moreover, the proposed thermal runaway mechanisms of high‐Ni (Ni ≥ 80%) LIBs are also reviewed to provide useful perspectives for the design of high‐safety electrolytes. Finally, the potential research directions of electrolyte engineering toward high‐performance high‐Ni (Ni ≥ 80%) LIBs are provided. This review will have an important impact on electrolyte innovation as well as the commercial evolution of high‐Ni (Ni ≥ 80%) LIBs, and also will be significant to breakthrough the energy density ceiling of LIBs.

The future nickel metal supply for lithium-ion batteries

“…2c). 53,54 LiF and some byproducts such as MnF 2 , CoF 2 , and NiF 2 are formed by the erosion of HF to lithium residues on the particle surface and dissolution of excess metal ions, respectively. 55 Lastly, the intergranular microcracks among primary particles or second particles are produced owing to the anisotropic lattice variations and structural collapse, which can enlarge the exposed internal surface and provide a channel for electrolyte penetration into the interior particles (Fig.…”

“…80 The common electrolyte additives have fluorinated compounds, boron-containing compounds, sulfur-containing compounds and phosphorus-containing compounds. 54,81 A single improvement method can enhance the stability of Ni-rich cathode materials, but the degree of improvement is limited. Therefore, the combination of modified methods is expected to further enhance the stability by employing their synergistic effects, such as combination of doping and coating, 82 microstructure refinement and surface modification.…”

Failure of Lithium-Ion Batteries Accelerated by Gravity

“…So far, significant effort has been directed toward comprehending the structural degradation and restoration behaviors of cathode materials, to ensure their high economic value and their capacity for lithium-ion (de-) intercalation. − However, the evolution of electrolytes, which remains one of the least addressed subjects in the literature on LIB degradation mechanisms, warrants immediate and thorough attention to ensure safer and more widespread utilization of LIBs. − In principle, a minor amount of electrolyte decomposition may not significantly impact battery performance when there is excess electrolyte. However, the limited amount of electrolyte used in batteries to achieve high-energy density, coupled with their prolonged service life and bulkiness, necessitates scrutiny.…”