Study On The Method And Mechanism Of Ship NO_x And SO₂ Removal Based On O₃-Na₂SO₃/Urea Syste

With the increasing popularity of electric vehicles,lithium-ion batteries（LIBs）are moving in the direction of high energy density and fast charging.The high specific capacity and lowest potential of lithium（Li）metal is a competitive candidate for the anode electrode of LIBs,but the Li metal will be accompanied by significant volume expansion during the deposition/stripping process,and the uneven deposition of Li will accelerate the growth of Li dendrites,which will seriously affect the stability of the battery,and even cause a safety accident due to an internal short circuit of the battery.Therefore,inhibiting the growth of Li dendrite is of great significance for the development of Li metal anodes.The solution adopted in this thesis is alloy interface layer modification and 3D structure design.The research content of this thesis mainly includes the following parts.Lithophilic Ag and Au interfacial layers are successfully prepared on the surface of Cu foil by a simple electroless plating method.Ag exists on the surface of Ag@Cu in the form of elemental substance,and Au exists on the surface of Au@Cu as zero-valent Au Cu.The smaller impedance and higher Li-ion migration number make Ag@Cu have more excellent electrochemical performance.Although Ag@Cu can cycle stably for 250 cycles at a current density of 0.5 m A cm^-2,and the initial deposition overpotential of the first cycle（38 m V）is only half of Au@Cu,but the voids and tiny dendrites on the surface of Ag@Cu are not conducive to long cycling.Especially at high current density,the inhibitory effect of Ag@Cu electrode on Li dendrite still needs to be improved.Using a simple electroless plating method,lithiophilic Cu₃Sn and Cu₆Sn₅ alloy interface modification layers are successfully prepared on the surface of Cu foil through a single temperature control.Due to the rough surface and large interphase resistance of Cu₃Sn@Cu,Li metal is deposited on its surface by a"preferred-deposition"mechanism of multi-directional growth.The uniform surface morphology,high electrolyte wettability and Li metal reaction kinetics of Cu₆Sn₅@Cu make the deposition mechanism of Li metal on its surface to be"parallel-deposition"with unidirectional simultaneous growth.A more reasonable deposition mechanism enables Cu₆Sn₅@Cu to exhibit excellent rate capability,and can inhibit the growth of Li dendrites.Based on the excellent lithophilicity and lithium deposition mechanism of Cu₆Sn₅,a uniform Cu₆Sn₅ interfacial layer is formed on the surface of 3D Cu foam by a simple electroless plating method.At a current density of 1 m A cm^-2,the cycle life of the composite electrode designed with 3D structure is increased from the original 650 h to 1000 h,and the overpotential is only 18 m V.And even at a high current density of 5 m A cm^-2,the Cu₆Sn₅@Cu foam can still be cycled for 200 cycles.Further in-situ online observation of Li metal deposition proves that Li metal can be uniformly deposited on Cu₆Sn₅@Cu foam surface and inhibit the generation of Li dendrites.Using a simple carbonization method,a self-doped N 3D sponge carbon（SC）with excellent flexibility is prepared.The flexible skeleton structure of SC with interconnected triangular branches can keep the structure intact during the cycle.The large distribution of pyridine N and pyrrolic N in the SC structure can improve its surface activity,promote the uniform deposition of Li and inhibit the formation of dendrites.The small resistance value and higher Li-ion migration number of SC make it have a rapid Li ion electrochemical process.The SC has a cycle life of up to 1800 h,and still has a high Coulombic efficiency of98%after 450 cycles.Li metal can be uniformly deposited on the surface of SC structures,thereby suppressing the formation of dendrites.In conclusion,this thesis investigated the effect of alloy interface layer modification and3D structure design on the inhibition of lithium dendrites in Li metal anodes.The combination of lithiophilic interface layer modification and 3D electrode structure design proposed in this thesis provides new insights for solving the volume expansion of Li metal and suppressing the formation of Li dendrites,which has reference significance.