Flexible Generator Based On Layered Double Hydroxide Driven By Water Evaporation

Great attentions have been paid on the waste energy in natural environment and daily life,such as thermal energy in environment,low frequency mechanical energy produced by human body movement,kinetic energy of raindrop falling.These natural waste energies are enormous without any pollution.As a ubiquitous natural phenomenon,water evaporation absorbs environmental thermal energy.Nevertheless,in most cases,the absorbed environmental thermal energy are not effectively collected or transformed into electricity.In 2017,scientists have realized the conversion of environmental thermal energy into electricity using water evaporation.They used nano-carbon materials as the working substance,as the water evaporated from the wet carbon materials,environmental energy were convert into electrical energy.Moreover,they have successfully powered the integrated circuit devices,which paved the way for the conversion of environmental thermal energy into electricity energy.In these works,as a working material,the carbon blacks were produced by incomplete combustion of organic matter.At the same time,special processes were needed to modify the properties of the material,such as high temperature annealing and plasma treatment.Consequently,this technology was limited to the high temperature resistant rigid substrates such as quartz or sapphire,which will undoubtedly restrict its application.It is necessary to develop a new technique to fulfill collecting and utilizing of the environmental thermal energy by water evaporation.It should be easily conduct as well as widely candidates of substratesIn this paper,the layered double hydroxides?LDHs?have been used for collection and conversion of environmental thermal energy into electric energy induced by water evaporation.We systematically studied the structure,morphology,chemical composition,surface charge and other properties of Ni/Al-LDH materials.Subsequently,multi-walled carbon nanotubes were used as electrodes and the Ni/Al-LDH thin film was used as working material.A Ni/Al-LDH flexible nanoscale generator driven by water evaporation was fabricated on the flexible PET by brushing method at room temperature.Single device?working area of 10 cm×1.5 cm?can provide the open circuit voltage of 0.7 V and short circuit current of 1.3?A.The maximum output power was 12?Wcm^-3.The device fabricated by this comparatively simple technique with desirable flexibility can power the integrated circuit,which makes a great progress for development of collection and conversion of environmental thermal energy into electric energy.