Fabrication And Electrochemical Performance Research Of AZO Coated 3D Cu/Li Metal Anode

Metal Lithium has a higher theoretical specific capacity(3840 m Ah/g)and a lower oxidation-reduction potential(-3.04 V),which is hailed as one of the promising new generation lithium battery anode materials.However,the growth of lithium dendrites on the surface of the electrode is not controlled and the side reactions between lithium and electrolyte are prone to occur during the cycling of lithium metal,which leads to poor circulation stability and security performance of lithium metal anode.In this paper,the structure of lithium metal negative electrode will be modified from the viewpoint of inhibiting the growth of lithium dendrites and reducing the side reactions of lithium metal and electrolyte.Finally,a three-dimensional composite lithium metal negative electrode material with excellent rate cycling performance and without the generation of lithium dendrites is prepared.It provides a reference for the research of lithium metal anode.The three-dimensional copper/lithium metal anode was prepared by high temperature melting method,and the effect of the preparation process of the anode on its electrode structure and electrochemical properties was studied by some physical characterization testing.The results show that the distribution of lithium in the threedimensional copper/lithium metal anode materials is uniform and the high chemical reactivity of elemental lithium is still maintained under the condition of 450 ?.Compared with the metal lithium anode,the discharge specific capacity is increased to 67.4 m Ah/g after 500 cycles at 20 C rate current,the cycling performance is increased by 65.6%.After 500 cycles,there is no obvious lithium dendrite on the surface of three-dimensional copper/lithium metal anode.The three-dimensional porous structure of copper foam significantly improves the real surface area of lithium metal,reduces the real current density on the surface of the electrode,helps to stabilize the formation of SEI film,inhibits the growth of lithium dendrite,and ultimately improves the cycling stability and safety performance of lithium anode.In order to improve the wettability between copper foam and liquid metal lithium,the magnetron sputtering was used to prepare the aluminum doped zinc oxide(AZO)coated copper foam.Preparing the AZO coated three-dimensional copper/lithium anode by high temperature melting method,and studying the effect of different magnetron sputtering process parameters on the structure and electrochemical performance of the AZO coated three-dimensional copper/lithium anode by some physical characterization testing.The results show that after the deposition of AZO layer coated by magnetron sputtering,the temperature of molten lithium was reduced from 450 ? to 350 ?,the rate of liquid lithium entering the three-dimensional structure of the material was significantly faster,and the distribution of lithium in the three-dimensional copper/lithium metal anode materials became more uniform than before.Compared with the three-dimensional copper/lithium metal anode,the discharge specific capacity is increased from 67.4 m Ah/g to 97.8 m Ah/g after 500 cycles at 20 C rate current,the cycling performance is increased by 45.1%;the electrode interface electrochemical impedance before charge-discharge cycle is not significantly changed.The high-rate cycle performance is significantly improved again.After 500 cycles,there is still no obvious lithium dendrite on the surface of AZO coated three-dimensional copper/lithium metal anode.The main reason for the performance improvement is that AZO has the affinity for lithium,which can significantly reduce the preparation temperature of AZO coated three-dimensional copper/lithium metal anodes.At the same time,the AZO layer participates in the film formation of the SEI film during the cycling of the electrode,which makes the resulting SEI film more stable.The surface of the SEI film becomes smoother,and the inhibitory effect on the growth of lithium dendrite increases again.