Interfacial Chemical Modulation Of Zinc Anode And Its Application In Aqueous Zinc-ion Batteries

The development of new large-scale energy storage technology with high economic applicability and environmental friendliness is an important issue that needs urgent research in the current energy storage industry.High-safety and low-cost aqueous zinc ion batteries are expected to meet the demand for large-scale energy storage.However,zinc negative electrode has serious problems of dendrite growth,corrosion and hydrogen precipitation,which reduce the cycle life of zinc ion batteries.In this thesis,to address the above problems of metallic Zn cathodes in aqueous batteries,a series of zinc electrode material systems with good stability are constructed by using interface regulation strategies such as porous interface layers,homogeneous heterogeneous metal interface modification and crystal surface modulation to optimize the electrochemical behavior of Zn cathode surface zinc deposition/exfoliation.The main research of this dissertation is as follows:1.In this work,porous titanium nitride nanosheets(h-TiNs)with high electrical conductivity and high specific surface area were prepared by the template method,and the combination of X-ray absorption spectroscopy and X-ray photoelectron spectroscopy together confirmed the abundant defect states on the surface of the nanosheets.The high electrical conductivity of the interfacial layer of titanium nitride inorganic material was utilized to accelerate the charge transport process in the electrochemical deposition of zinc,and its defect structure provided uniform nucleation sites for zinc;the titanium nitride interfacial layer also exhibited an inhibitory effect on corrosion reactions.h-TiNs@Zn negative electrode exhibited a stable electrochemical behavior,stable at a current density of 1 mA cm-2 cycle for 670 h and 600 cycles of stable operation at a current density of 0.5 C.2.In this work,the coordination of thiourea molecules was used to regulate the nucleation process of the substitution reaction between heterogeneous metal ions and Zn,achieving the uniform deposition of heterogeneous metals on commercial Zn foils,including Sn,Cu,and Ag with Znophilic properties.The symmetric cell assembled with Sn@Zn electrode was stable for more than 900 h at a current density of 20 mA cm-2(a capacity of 5 mAh cm-2),and the full cell was stable for more than 1000 cycles at a current density of 1 C,with a capacity retention rate of 98.2%.3.In this work,rapid deep cryogenic process was used to obtain(002)crystal surface coarse crystals to accelerate secondary recrystallization process.Combined with metallic zinc properties,it is easy to deform along slip system,and increase the ratio of(002)crystal surface in zinc anode.By constructing high proportions of(002)crystalline zinc anode,it is possible to effectively suppress hydrogen deposition and realize horizontal deposition of zinc.The symmetrical cells assembled with deepcryogenic treatment zinc anodes are stable for more than 2400 h at a current density of 1 mA cm-2(a capacity of 1 mAh cm-2),and assembled the full cells are stable for 1300 cycles at a current density of 2 C.