Due to the small size and battery capacity of sensor nodes in wireless sensor networks, energy control problems arise. Numerous studies have used energy-saving techniques to address these problems in sensor networks. The purpose of this study was to gather information on various energy-saving strategies used to keep sensor nodes’ batteries fully charged between 2016 and 2021. Additionally, this review article addresses issues, fills in knowledge gaps on rechargeable wireless sensor networks, schedules techniques for monitoring nodes’ life spans, and a number of measures to improve nodes’ efficiency and scalability in rechargeable sensor networks.