Advanced electrolyte systems with additives for high-cell-voltage and high-energy-density lithium batteries

Abstract

Given that battery-powered electric vehicles and other power equipment put forward higher requirements for long recharge mileage, the development of high-performance lithium batteries (LBs) has become necessary. Accordingly, one of the effective ways to achieve this is to increase the cell voltage and energy density of LBs. However, these high-cell-voltage and high-energy-density LBs face the challenges of severe electrolyte decomposition and electrode corrosion in a high-voltage environment. In this review, the issues associated with the electrolyte for high-cell-voltage and high-energy-density LBs are comprehensively reviewed in terms of the types of electrolytes and electrolyte additives, their functional mechanisms and their performance validation. Also, we focus on electrolyte ion solvation and the internal solvent structure based on both solution chemistry and solvation theory. Both the high concentration strategy and solvent modification are identified to be effective in improving the performance of high-cell-voltage and high-energy-density LBs. In addition, the selection of new organic lithium salts instead of traditional lithium salts and electrolyte additive design have also been identified to be important ways. To facilitate further research and development, herein, some technical challenges are analyzed and the future research directions for overcoming the discussed challenges are also proposed. This review may provide theoretical support for electrolyte design and additive selection for high-cell-voltage and high-energy-density LBs in future.