Design And Research Of Photorechargeable Devices Based On Nickel-Based Capacitors

Photorechargeable devices can simultaneously collect,convert,and store solar energy,which solves the problems of unstable solar power generation and the need for external charging of energy storage batteries,and has broad development prospects.The material system selection and device structure design are the research focuses of photorechargeable devices.The energy conversion efficiency of photorechargeable devices is jointly affected by the photovoltaic and energy storage parts.Among them,improving the energy efficiency of the energy storage part is of great significance for photorechargeable devices,and the electrochemical performance of the energy storage part often depends on the electrode materials.This paper starts with the modification of electrode materials,and improves their electrochemical performance and the corresponding overall energy conversion efficiency of the photorechargeable devices through element doping and ion intercalation.The main research contents are as follows:（1）Through La-doping modification of the Ni（OH）₂ electrode material,the energy efficiency of Ni（OH）₂-based asymmetric capacitors was improved,and a photoelectric storage integrated device was successfully constructed.Under the optimal synthesis conditions,the La-Ni（OH）₂ electrode material obtained had a specific capacity of up to 155.6 mAh·g^-1 at 2 A·g^-1.The energy efficiency of the assembled asymmetric capacitor was as high as 68.01%.The photorechargeable device constructed had an energy storage efficiency of 70.59%and an overall energy conversion efficiency of up to 12.96%.It was found that the introduction of La reduced the crystal cell volume,significantly shortened the diffusion distance of protons/ions,and accelerated the reaction.At the same time,La could change the surface electron structure of Ni（OH）₂,increase crystal defects,improve the electrical conductivity of the material,greatly improve the electrochemical performance of the material,and thus enhance the overall energy conversion efficiency of the corresponding photorechargeable device.（2）Through the preparation of nickel-aluminum layered double hydroxide（NiAlLDH）with chloride ion intercalation by the acid salt treatment,the energy efficiency of NiAlLDH-based asymmetric capacitors was improved,and the overall energy conversion efficiency of the photorechargeable device was greatly increased.Under optimal experimental conditions,the NiAlLDH electrode material obtained has a specific capacity of up to 230.1 mAh·g^-1 at 2 A·g^-1.The energy efficiency of the assembled asymmetric capacitor is as high as 74.95%.The constructed photorechargeable device has an energy storage efficiency of 85.32%and an overall energy conversion efficiency of 16.12%.Analysis shows that Cl^-substitution for CO₃^2- in the LDH interlayer increases the interlayer spacing,promotes ion and proton transport,improves the electrochemical performance of LDH materials,and thus significantly enhances the overall energy conversion efficiency of the corresponding photorechargeable device.