Wireless Sensor Networks (WSNs) operating on constrained energy resources present a substantial challenge to researchers. Actually, a lot of ideas have been made to either equip a WSN's sensor nodes with technologies that harvest energy or to preserve the energy that it uses efficiently. This paper presents an Improved Energy-Efficient MAC Protocol for WSNs (IEE-MAC). The functioning of IEE-MAC relies on using transmitter-initiated schemes and low-power listening (LPL) with small preamble messages and based on the value of the collected energy rate, each sensor node in the WSN may decide when to sleep next. In doing so, it lowers the duty cycle more adaptively by utilizing the stored remaining energy, which particularly aids in minimizing latency and energy consumption. According to the simulation findings, our suggested protocol performs better in terms of lowering average latency and power consumption while boosting packet delivery rates as well as extending the lifetime of wireless network compared to the PS-EHWSN scheme.