Compressed-gas energy storage is an important technical approach to addressing the fluctuation problem of renewable-energy grid connection. However

in practical applications

challenges are still faced

such as the low utilization rate of waste heat and large throttling losses. The ejector can effectively recover expansion work

reduce throttling losses

and lower the pressure of the cushion gas

and can be integrated with compressed-gas energy storage systems in many efficient ways. This paper systematically reviews the basic principles and development status of compressed-gas energy storage technology

and focuses on analysing the integration methods and application effects of ejectors in different types of energy storage systems. Research indicates that the introduction of an ejector can enhance the cycle efficiency of the system by 2%–4.38%

resulting in an increase of ∼21% in the profit of the system. Additionally

incorporating an ejector can improve the energy storage density of the gas storage facility and enhance the cooling capacity of the system. Finally

based on the current situation

judgments are made on the existing problems and future development directions.