Studies On Novel Aqueous Rechargeable Hydrogen Gas Batteries

The ever-increasing global fossil fuel consumption has driven the rapid development of renewable energy,such as solar and wind,to reduce carbon emissions and environmental pollution.Battery as one of the energy storage systems with high energy and power performance has attracted much attention in enabling renewable yet intermittent sources.Among them,lithium-ion,lead-acid,redox-flow,and sodiumsulfur rechargeable battery systems show promise for large-scale energy storage(LSES)applications,but they still have many shortcomings,such as low safety of lithium-ion batteries and sodium-sulfur batteries,short life of lead-acid batteries,and high cost of redox-flow batteries.Therefore,the development of a new rechargeable battery system with long life,high safety,and low cost is the key to LSES applications.Due to highly efficient redox reactions of hydrogen gas electrode(low overpotential of～0 V),aqueous rechargeable hydrogen gas batteries(HGBs)have the advantage of long cycle life,high round trip efficiency,and fast reaction kinetics,showing highly desirable features for LSES applications.Although some progress had been made in the HGBs,systematic research on this subject remains rare.Therefore,this thesis focuses on the systematic development of novel aqueous HGBs with high safety,low cost,high power,long life,and all-climate properties for LSES,as shown specifically in the following five studies:1.Based on the excellent low-temperature characteristics of proton batteries,we developed a novel aqueous hydrogen gas-proton battery.This battery is composed of hydrogen gas anode,Prussian blue analogue(PBA)proton cathode and concentrated phosphoric acid electrolyte.Its operation involves hydrogen evolution/oxidation redox reactions on anode and H+insertion/extraction reactions on cathode.The fabricated aqueous hydrogen gas-proton battery delivered an ultrafast rate of 960 C and an ultralong cycle life of over 0.35 million cycles.Furthermore,this battery was able to work well at an ultralow temperature of-80℃ and keep a stable life of over 1150 cycles at-60℃.This work provides new opportunities to construct aqueous proton batteries with high performance in extreme conditions for LSES.2.In order to improve the working voltage of the battery based on the above PBA cathode material,we built new PB As-hydrogen gas hybrid battery systems in which the PBAs-based cathodes operate by insertion/extraction reactions with different cations(Na+,K+ or NH4+)and a hydrogen gas anode operates by electrocatalytic hydrogen evolution/oxidation reactions.The assembled PBAs-hydrogen gas hybrid battery exhibited a working voltage of 1.09 V.Furthermore,the hybrid battery showed a rate of 100 C and a cycling lifetime over 25,000 cycles.This work demonstrates a class of hydrogen gas hybrid batteries,paving the way for more hydrogen gas hybrid batteries.3.In order to make the HGB to have a better commercialization prospect based on the aforementioned hybrid battery systems,we designed a new lithium manganese oxide-hydrogen gas battery that exploited a commercially mature lithium manganese oxide cathode and a hydrogen gas anode in aqueous Li2SO4 electrolyte.The proposed lithium manganese oxide-hydrogen battery exhibited a high discharge potential of～1.3 V and a rate of 50 C.This work provides opportunities for the commercial development of new rechargeable HGBs for the future LSES.4.Solid electrodes often exhibit slowly ionic reaction,while electrodes with semisolid reaction show fast reaction kinetics.Therefore,we developed a novel highperformance aqueous iodine-hydrogen gas battery by using iodine cathode,electrocatalytic hydrogen gas anode,and eco-friendly aqueous electrolytes.The battery reaction includes solid-liquid reactions(I2/I’)at the cathode and gas-liquid reactions(H2/H2O)at the anode,achieving a rate of 100 C and long-lasting stability of over 60,000 cycles.Additionally,the aqueous battery delivered a volumetric capacity of 15.5 Ah L-1 along with good self-healing capability towards cell overcharge.This work not only broadens the reaction types of HGBs,but also provides a new idea for the design and development of halogen cells.5.Based on the high energy efficiency of liquid electrodes,we proposed an ironhydrogen gas battery with low-cost liquid cathode([Fe(CN)6]3-/[Fe(CN)6]4-)and hydrogen gas anode.The designed iron-hydrogen gas battery showed high energy efficiency of 93%and discharge plateau of～1.29 V at current of 10 mA.In addition,this battery exhibited energy efficiency of 73%even at high current of 60 mA and stable cycling life of over 20000 cycles.This work highlights significance of the deployment of liquid redox molecules as active species in HGBs,extending the HGB cathodes from solid to liquid.