All-liquid triboelectric nanogenerator for harvesting distributed energy

A method for producing power in a self-powered sensor using a liquid-liquid (L-L) contact electrification (CE) triboelectric nanogenerator (TENG) system, the method comprising:

• providing a first fluid volume comprising purified water or an aqueous solution, the first fluid volume having a first density;
• providing a second fluid volume comprising an oil, the second fluid volume having a second density different than the first density;
• providing an electrode having a positive terminal and a ground terminal,
• the positive terminal and the ground terminal having a direct connection to an electronic circuit comprising a capacitor in parallel with a load,
• the electrode contained within the second fluid volume,
• the electrode aligned vertically either above or below the droplet generator;
• providing a droplet generator in fluid contact with the first fluid volume and the second fluid volume;
• the first fluid volume having a first height (h1) above the droplet generator;
• the second fluid volume having a second height (h2) above the droplet generator;
• the first density having a value (ρ1);
• the second density having a value (ρ2);
• the first fluid volume, the second fluid volume, and the droplet generator each respectively configured and adapted such that when the equation:
• ρ
• 2
• ⁢
• h
• 2
• <
• ρ
• 1
• ⁢
• h
• 1
• is satisfied, a multiplicity of droplets of the aqueous solution are formed and released, each droplet, respectively, passing through the second fluid volume proximate the electrode, driven by the force of gravity acting upon the first density and the second density, respectively;
• wherein passage of the multiplicity of droplets proximate the electrode generates a displacement current between the positive terminal and the ground terminal;
• wherein the direct connection comprises a first switch (S1) between the electrode and the electronic circuit and a second switch (S2) between S1 and the load;
• wherein the circuit is characterized by the absence of any rectifier.

A liquid-liquid (L-L) contact electrification (CE) triboelectric nanogenerator (TENG) system for producing power in a self-powered sensor, the system comprising:

• a first fluid volume comprising purified water or an aqueous solution;
• a second fluid volume comprising an oil, the oil having a density different than the density of the purified water or aqueous solution;
• a droplet generator fluidly connecting the first fluid volume and the second fluid volume;
• an electrode having a positive terminal and a ground terminal, the ground terminal connected to ground or to a conductive material having a mass greater than the mass of the TENG;
• the positive terminal and the ground terminal having a direct connection to an electronic circuit comprising a capacitor in parallel with a load;
• the electrode contained within the second fluid volume;
• the electrode aligned above or below the droplet generator;
• the first fluid volume having a first height (h1) above the droplet generator;
• the second fluid volume having a second height (h2) above the droplet generator;
• the first fluid volume having a first density (ρ1);
• the second fluid volume having a second density (ρ2);
• the first fluid volume, the second fluid volume, and the droplet generator each respectively configured and adapted such that when the equation:
• ρ
• 2
• ⁢
• h
• 2
• <
• ρ
• 1
• ⁢
• h
• 1
• is satisfied, a multiplicity of droplets of the aqueous solution are formed and released, each droplet, respectively, passing through the second fluid volume proximate the electrode;
• wherein passage of the multiplicity of droplets proximate the electrode generates a displacement current between the positive terminal and the ground terminal;
• wherein the direct connection comprises a first switch (S1) between the electrode and the electronic circuit and a second switch (S2) between S1 and the load;
• wherein the system is characterized by the absence of any rectifier between the electrode and the electronic circuit;
• wherein the system exhibits (i) a charge density greater than or equal to about 3.63 μC/L, (ii) a CE time greater than or equal to about 1200 seconds, and (iii) an output stability greater than or equal to about 0.9.