Perspectives on Improving the Safety and Sustainability of High Voltage Lithium‐Ion Batteries Through the Electrolyte and Separator Region

Abstract

Lithium‐ion batteries (LIBs) are promising candidates within the context of the development of novel battery concepts with high energy densities. Batteries with high operating potentials or high voltage (HV) LIBs (>4.2 V vs Li+/Li) can provide high energy densities and are therefore attractive in high‐performance LIBs. However, a variety of challenges (including solid electrolyte interface (SEI), lithium plating, etc.) and related safety issues (such as gas formation or thermal runaway effects) must be solved for the practical, widespread application of HV‐LIBs. Most of these challenges arise in the region between the electrodes: the electrolyte region. This review provides an overview of recent development and progress on the electrolyte region, including liquid electrolytes, ionic liquids, gel polymer electrolytes, separators, and solid electrolytes for HV‐LIBs applications. A focus on improving the safety of these systems, with some perspectives on their relative cost and environmental impact, is given. Overall, the new information is encouraging for the development of HV‐LIBs, and this review serves as a guide for potential strategies to improve their safety, allowing the development of HV‐LIBs, including solid‐state batteries, to be accelerated to practical relevance.

Influence of Different Alginate and Carboxymethyl Cellulose Binders on Moisture Content, Electrode Structure, and Electrochemical Properties of Graphite‐Based Anodes for Lithium‐Ion Batteries

“…This is likely a combination of both the lower adhesion of the alginate binder and the higher moisture content (Figure 5 and 6), which can lead to unwanted side reactions the electrolyte and increase in cell impedance and lithium loss. [52,53] The C-rate results shown in Figure 8 demonstrate that the CMC-D anode performs very well during C-rate testing. The other anodes show relatively similar values, compared to the CMC-D anode, within overlapping standard deviations, aside from the CMC-A-anode, which performs worst at higher C-rates.…”

Exploring ionic liquid-laden metal-organic framework composite materials as hybrid electrolytes in metal (ion) batteries

“…This allows the design of solid-state batteries that operate with high-potential cathodes, and thus, can potentially provide high energy density values. Compared to other types of solid electrolytes, the combination of an IL with a MOF has important advantages ( Han et al, 2020 ; Cavers et al, 2022 ; Guo et al, 2022 ). The ionic conductivity of the IL@MOF hybrids is higher than that exhibited by the SPEs.…”

Advances in thermal‐related analysis techniques for solid‐state lithium batteries

“…[4][5][6] However, the emergence of new materials with higher energy and power density has also increased the safety risks of batteries. For example, high-voltage cathodes (e.g., Li-rich, high nickel cathode, high-voltage LiCoO 2 ) have been developed to deliver higher energy density, [7][8][9][10][11] but the elevated operating voltage and highly active cathodes with high-valance transition metal pose unprecedented challenges to electrolyte stability. Lithium metal anode with a high theoretical capacity of 3860 mAh g À1 and lowest voltage (À3.04 V, vs. SHE) is considered as the "holy grail" anode, but triggers severe electrolyte decomposition and lithium dendrites formation.…”