Design And Application Of High Performance Aqueous Zinc-Iodine Batteries

The global demand for economically sustainable energy storage is growing rapidly,due to the mounting alarm about environmental pollution and the need to reduce greenhouse gas emissions.Battery technology has become a major part of today’s energy storage system due to its safety,efficiency,affordability,and versatility as an electrochemical energy storage device.This paper will explore the practicality of high-performance battery applications.High-safety,long-life aqueous zinc-iodine secondary battery energy storage system,from the construction of efficient iodine-carrying cathode materials,to achieve wide temperature range of high performance and industrial application prospects,to explore the impact of structure and N doping on iodine storage mechanism.To design a new aqueous zinc-iodine secondary battery with high energy density,cost-effectiveness,robust safety,and environmental sustainability,the research work is mainly carried out in the following aspects.In terms of exploring the mechanism of iodine adsorption by porous structure and N doping,layered porous carbon materials with high pyridine nitrogen doping and interporous micro-mesoporous structure can be prepared by a reasonable raw material ratio and a simple one-step sintering method.The effects of porous structure and different N doping types on the effective adsorption of elemental iodine are systematically studied.The high micropore ratio of layered porous carbon materials can provide effective strong binding for elemental iodine.Meanwhile,the enhanced chemical adsorption of iodine species by high pyridine nitrogen doping can further enhance the strong adsorption effect of elemental iodine,achieving an efficient iodine binding of up to 61.6 wt%.At the same time,the mesoporous structure interconnected with micropores provides good electrolyte adsorption and wetting effects,and higher graphite nitrogen doping can also provide higher conductivity for the layered porous carbon material,which provides a theoretical basis for the positive electrode of high-performance Aqueous Zn-iodine batteries.The unique layered porous carbon and iodine composite（I₂@NHPC）with large micropore volume and abundant N doping significantly improves the electrochemical performance and stability of the positive electrode.Combined with the aqueous phase electrolyte,which inhibits the growth of metal zinc dendrites,high-performance and long-life aqueous zinc-iodine batteries were prepared.The electrochemical performance at room temperature was emphatically studied.Abundant pyridine N active sites can promote electron transfer in the electrochemical process,reasonable pore size design can firmly anchor the active substance iodine,and the interconnected micromesoporous structure can promote the diffusion of Zn²⁺,and cooperate to promote the REDOX kinetics of the aqueous zinc-iodine battery.The iodine cathode of high load exhibits remarkable coulomb efficiency,cycle stability,and rate performance;moreover,the initial device constructed from three cells in succession can generate a high energy density of up to 72.6 Wh kg^-1,as determined by the total mass of the cell.This is almost twice as fast as commercial aqueous lead-acid and nickel-cadmium batteries.The aqueous battery exhibits remarkable promise for extensive energy storage applications owing to its exceptional energy density and prolonged lifespan in cycles.In this paper,the suitable electrolyte with high conductivity in a wide temperature range is prepared by screening suitable solute materials,and a small amount of anti-temperature additives are added to ensure the configuration of a combination electrolyte with high safety and excellent stable cycling performance in a wide temperature range（-60℃-+60℃）.The new combined electrolyte has an ultra-low freezing point that does not freeze at-98℃,while maintaining high ionic conductivity at low temperatures,and can be used in aqueous Zinc-iodine batteries with a wide temperature range.The combined electrolyte can also show the following advantages even at extreme temperatures.First,the concentrated electrolyte has low freezing point,high ionic conductivity,low volatility and good compatibility with zinc metal,which can greatly reduce the working temperature of the aqueous zinc-iodine battery and ensure the excellent electrochemical performance of the aqueous zinc-iodine battery in a wide temperature range.The concentrated electrolyte’s wide voltage window,providing excellent thermal and electrochemical stability,is conducive to the battery’s stable operation across a broad temperature range.This guarantees that the I₂battery prepared in aqueous form will have good electrochemical performance in temperatures ranging from-60 to+60℃.A aqueous zinc-iodine soft pack battery with high energy density and long cycle life was designed by using the above prepared unique layered porous carbon and iodine composite（I₂@NHPC）with large micropore volume and abundant N doping as the positive electrode,industrial grade metal zinc as the negative electrode,and a new type of combined electrolyte as the electrolyte.The actual energy density of the cell reaches 62 Wh kg^-1,which achieves the design goal.The effects of slurry viscosity and voltage range on the electrochemical performance and safety of aqueous zinc-iodine soft pack batteries were investigated.Under the system and process conditions,the positive slurry with a viscosity of 3500 m Pa·S has more advantages in cycle stability.When the charging and discharging voltage range is 0.9-1.4V,the cycle performance and energy density are more advantageous.Finally,the safety performance tests of the aqueous zinc-iodine soft pack battery were carried out by stamping,puncture and shear.The results showed that no smoke,fire and explosion occurred in the test process,and the battery test results were excellent.Experiments show that the aqueous zinc-iodine battery has excellent safety performance.