Research Of Highly Compatible Cathode Material Based Seawater System For Energy Storage

Under the background of double carbon policy and the global energy crisis,clearly renewable energy is developing rapidly.The boom of clear energy caused the urgent demand of large-scale energy storage devices with eco-friendliness,low cost and excellent performance to overcome the inherent uncertainly of secondary energy.Seawater,as a natural resource,is inexhaustible.Utilizing seawater as the electrolyte for the energy storage system is not only low-cost,but also safe and environmentally friendly in nature.Based on the Zn-based anode,this paper explores and develops cathodes material suitable for seawater electrolyte to build seawater-based energy storage,which opens up a new direction for large-scale energy storage devices.（1）Starting from the carbon-based materials with stable structure and high conductivity,the activated carbon electrode displayed high activity in seawater-based electrolyte（HS-Zn SO₄）by electrochemical test,which preliminarily proved the feasibility of seawater as the electrolyte of energy storage system.（2）After that,Ni（OH）₂nano-flower-shaped material was prepared by simple hydrothermal method.It was verified by a series of electrochemical measurements that it could work well in seawater-based electrolyte HS-KOH and exhibited high compatibility with seawater-based electrolyte.At the same time,its energy storage mechanism in seawater-based electrolyte was revealed by in-situ impedance test.The supercapacitor energy storage device Ni（OH）₂-NF//Zn showed a discharge capacity of 155 m Ah g^-1at a current density of 0.5 A g^-1,and it could be successfully charged.Show a good application prospect.（3）350-NiO material was obtained by calcining Ni（OH）₂at different temperatures.Through physical tests and electrochemical tests,it was determined that the electrode made of NiO obtained at 350℃exhibited the best performance in seawater electrolyte HS-KOH,and the discharge capacity could reach 150 m Ah g^-1.At the a current density of0.5 A g^-1,it stably circulated in seawater-based electolyte for nearly 10000 cycles,which proved that 350-NiO obtained by calcination was more compatible with seawater electrolyte,presenting the potential of 350-NiO as the cathode material of seawater energy storage system.