Electricity generation from ionic solution flowing through packed three-dimensional graphene powders

Herein, we demonstrate a distinctive energy harvesting method that electricity can be generated from the ionic solution flowing through the interstices between packed three-dimensional graphene powders. A constructed electrokinetic nanogenerator with an effective flow area of ∼0.34 cm²can generate a large current of 91.33 nA under 10^-6M NaCl solution with a flow rate of 0.4 ml min^-1, corresponding to a maximum power density of 0.45μW m^-2. Besides, it shows a good linear relationship between the streaming current and the flow rate, suggesting that it could be used as a self-powered micro-flowmeter. These results provide a convenient way for clean energy harvesting and show a bright future for self-powered systems.