Preparation, Processing And Performance Research Of Nanoporous Mn-based Medium-high Entropy Alloy Current Collecto

Lithium ion batteries（LIBs）are widely used in the field of portable electronic devices because of their high energy density and long cycle life.In order to further improve the performance of LIBS,it is of great significance to develop new electrode materials.Transition metal oxides（TMOs）have been widely studied because of their rich reserves,high theoretical specific capacity and low price.As the electrode material of LIBS,the high entropy oxides composed of five or more elements have higher theoretical specific capacity.Because micron electrode materials are difficult to achieve high storage capacity,nano materials can effectively improve their specific surface area,expose more active sites,shorten the diffusion distance of lithium ions,so as to improve higher capacity.However,the disadvantages such as poor conductivity of TMOS and high expansion coefficient in the process of charge and discharge,resulting in poor stability and magnification performance,limit its development.In this paper,through the overall design and reasonable calculation of the electrode,the transition metal medium and high entropy alloy strips were prepared according to the specific atomic ratio,and the nano porous powder was prepared by dealloying technology.Then,through deep oxidation,increase the load of active substances,hydrogen reduction and carbon coating,improve the structural stability of nano porous junctions and reduce their internal impedance,so as to realize high-performance lithium-ion battery cathode materials,which have good research prospects.The specific research results are as follows:（1）Based on a reasonable design scheme of nano porous NiCuCoMn quaternary alloy electrode,single-phase quaternary metal oxide is obtained by spontaneous combustion and hydrogen reduction.The single-phase quaternary metal oxide has good stability and maintains the original rock salt structure in the process of lithium intercalation/lithium removal.At the same time,after hydrogen environment,oxygen enriched vacancies and zero valent copper atoms form a local electric field,which improves the transmission capacity of Li⁺.The electrode showed excellent electrochemical performance on these basis.After 200 cycles,it maintained 615 and485 m Ah g^-1 at 0.1 and 1 A g^-1.（2）Five element alloy strips were prepared with five transition metal elements of Ni,Cu,Fe,Co and Mn in a certain proportion.After dealloying,the wet nano porous metal will spontaneously ignite in air atmosphere to form nano porous high entropy metal oxides with uniform distribution of five elements（NCFCM@HEOs）,Because of the entropy stabilization effect,the storage capacity of high entropy oxide electrode is maintained,and the cycle stability is greatly improved.Then hydrogen reduction and carbon coating were carried out to distribute the metal/oxygen vacancies in the mixed crystal structure,which improved the lithium storage capacity.The results show that after carbon coating reduction C@R-Ni Cu Fe Co Mn@HEOs high entropy oxide electrode can reach 890 m Ah g^-1 when the current density is 0.1 A g^-1.Even after 200discharges,the capacity can still reach 801 m Ah g^-1.Under the high current density of1 and 2 A g^-1,the battery capacity can still reach 470 and 538 m Ah g^-1 respectively after200 cycles.