Flow-induced Voltage Generation In Graphene Network

In this work, we fabricated a criss-cross structured and low cost graphene network(GN) via chemical vapor deposition(CVD). In order to acquire this unique construction, we took copper mesh instead of copper film as grown substrate. We tested two types of fluid, one was the droplet of ionic solution and the other one was continuous ionic liquid. In response to the movement of a droplet of ionic solution over a GN strip, a voltage of several hundred millivolts is observed under ambient conditions. When the droplet is drawn into moving on the GN, ions were absorbed at the front end, advancing the pseudocapacitor forward and drawing electrons in GN. Meanwhile, ions were being desorbed at the rear of the droplet, discharging the pseudocapacitor and releasing the electrons to the GN. Besides it, when the continuous ionic liquid flowed on the GN, the consistent voltage could be detected obviously. In these phenomena, the special structure of GN plays an important role in improving the rate of electron transfer and splitting the continuous fluid into “droplets” to generate voltage. There were several impact factors in generation process, such as mesh, flow rate, direction of motion and so on.In the follow-up experiment, we chose different types of copper mesh as substrate and found the optimized mesh was 100. By maintaining other effect factors, we discovered that the slope with an inclination of 45 o was most appropriate.All of above results prove that GN has great potential in energy conversion and flow sensor.