| Solid-liquid dual-phase triboelectric nanogenerator(TENG)is a new type of energy harvesting device,compared with the traditional solid-phase triboelectric nanogenerator.The solid-liquid biphasic coupling can significantly enhance its output characteristics,service life,friction characteristics,wear and aging performance.In this study,polytetrafluoroethylene(PTFE)was used as the surface friction material of solid friction layer,and electrostatic spun PCL was used as the solid state friction layer structure material,using the eutectic Ga In liquid metal alloy as the liquid friction layer material.Firstly,the surface of Ga In liquid metal alloy was treated by boiling deionized water and sodium chloride solution.The surface topography of the alloy was analyzed and the effect of the solution state on the reaction process during the treatment was analyzed.The solidliquid dual-phase friction process was then analyzed using the first principles,as a result,the reaction was carried out using COMSOL Multiphysics software performs finite element simulation analysis of the device operating process.The surface of the untreated eutectic Ga In liquid metal alloy was coated with Ga2O3,and the surface oxide and morphology of the liquid metal surface are changed by two surface treatment methods: boiling in deionized water and boiling in sodium chloride solution.Boiled in deionized water or Na Cl solution within a certain time,white rodshaped crystals will form on the surface.When boiled in deionized water,Ga OOH clusters will form on the surface of gallium indium alloy.When LM is boiled in Na Cl solution,increasing Na Cl concentration,and Ga OOH crystal morphology changes from club-like nodules to cells and then to regular cuboid cubes.In addition,in the process of surface treatment,reaction conditions such as boiling state of solution have great influence on the formation of final surface products.The feasibility of electrospinning PCL microstructure was investigated,and the influence of the velocity of nozzle relative to the collector plate on the microstructure of PCL was analyzed.Finally,the optimum technological parameters were obtained,and the PCL microstructure with average diameter of 150 μm,spacing between two lines 650 μm and thickness of 10 μm was successfully prepared.On the other hand,based on the first principle,the CASTEP module in Materials Studio was used to construct the molecular models of PTFE,Ga2O3 and Ga OOH.Taking the most widely used Al-PTFE system as a reference,the contact state of Ga2O3-PTFE system and Ga2O3-PTFE system as well as the charge transfer during the contact friction were calculated.The friction power generation capacity of Ga2O3-PTFE system was 1/3 of that of Al-PTFE system.The friction power generation capacity of the Ga OOH-PTFE system is 11/12 that of the Al-PTFE system.Using result of first-principles calculations before in COMSOL Multiphsics software,taking the finite element analysis of the contact friction process of Ga2O3-PTFE and Ga OOH-PTFE to establish solid-liquid dual-phase two-dimensional model.Based on this model,calculations were made to determine the optimal fill-liquid ratio as 1/2,the peak inter-polar friction in Ga2O3-PTFE contact 26 k V potential difference,79 k V peak potential difference between plates when Ga OOH-PTFE contact friction.The surface treatment resulted in a significant improvement in the charge accumulation capacity and peak potential difference output during operation of the triboelectric nanogenerator based on eutectic gallium-indium alloy. |
