The idea of harvesting electricity from mechanical energy encourages research for new technologies. Two popular mechanisms can be used to convert kinetic energy into electrical energy: electromagnetic and electrostatic. On the micro-scale, electrostatic generators are more suitable than electromagnetic generators. In this scenario, the capacitor-based electrostatic generators can be a suitable candidate as capacitors may provide higher power density and efficiency as well as long cycle life. The air gap between dielectric and capacitor plates is one of the bottlenecks for efficient energy generation. It is required to maintain a small air gap for rotating devices to avoid friction. Here, we proposed an efficient method to reduce the effect of the air gap and to enhance the efficiency of the generator. Firstly, one surface of both electrodes is oxidized using the standard anodization process. The oxidized surface acts as a dielectric layer; the thickness and porosity of layers play an important role. Later, an electrolyte-soaked membrane is placed between both oxidized electrodes in a parallel arrangement. The axial movement of electrodes against each other is done to decrease the capacitance. As a result, the electrostatic energy of the capacitor increases significantly, as capacitance (C) decreases (E = Q²/2C). Importantly, the charge (Q) on capacitor plates should be constant. The capacitor is disconnected from the voltage source after charging to maintain a constant charge. The proposed electrostatic generator is useful for portable electronic devices, such as mobile phones, global positioning systems, and medical devices.