Porous Carbon Coated Metal(Cobalt/ Nickel) And Its Oxide Electrochemical Energy Storage Research

Because porous carbon composites have the advantages of low density,good thermal conductivity,high specific surface area and low expansion coefficient,they have attracted much attention in recent years.Nickel,cobalt and its oxides because of its theoretical capacity of lithium batteries higher,electrochemical catalytic oxygen and oxygen reduction performance is better,has recently been widely studied.However,during the electrochemical reaction,the volume expansion of nickel,cobalt and its oxides is large,leading to the collapse of its structure,so that its stability is reduced.Therefore,increasing the electrochemical stability of nickel,cobalt and its oxides is a very important issue.Therefore,in this paper,we use porous carbon-coated nickel,cobalt and its oxides to improve the stability of the material,thereby improving its electrochemical performance.In this paper,we synthesized Co₃O₄@CoO@Co@C and NiO@Ni@C two kinds of porous carbon composites and studied the electrochemical properties of the materials.We prepared three kinds of porous carbon composites with different mass ratio and studied the properties of these three kinds of porous carbon composites as lithium ion battery and zinc air battery electrode materials.Electrochemical and catalytic performance of Co₃O₄@CoO@Co@C-2/1 nanocomposites is more excellent than Co₃O₄@CoO@Co@ C-1/1 and Co₃O₄@CoO@Co@C-1/2.Co₃O₄@CoO@Co@C-2/1 lithium-ion battery test show that discharge capacity can maintain 450 mAhg-1 and coulombic efficiency is nearly 100% during 500 cycles for LIBs.Co₃O₄@CoO@Co@C-2/1 as catalyst of OER shows excellent electrochemical durability over 15 hours continuous experiment.oxygen evolution reactions?OER?,oxygen reduction reactions?ORR?double catalyst and zinc air battery test were used for Co₃O₄@CoO@Co@C-2/1.In the OER test,the starting potential of Co₃O₄@CoO@Co@C-2/1 was 1.58 V and at 1.9 V the current density of the catalyst was 142.0 mAcm-2.In the ORR test,the initial potential,half-wave potential and ultimate diffusion current density at 1600 rpm were 0.85 V,0.65 V and 4.3 mAcm-2,respectively.Zinc air battery test,Co₃O₄@CoO@Co@C-2/1 of the initial charge and discharge voltage of 1.05 V,resulting in a voltage efficiency of 42%.50 hours after 50 cycles,the potential of charge and discharge turn to 0.7 V.In the second part,we synthesized three kinds of composites NiO@Ni@C-2/1,NiO@Ni@C-1/1 and NiO@Ni@C-1/2.The electrochemical and catalytic properties of NiO@Ni@C-2/1 nanocomposites is higher than NiO@Ni@C-1/1 and NiO@Ni@C-1/2 for nickel/carbon precursors with different atomic ratios excellent.NiO@Ni@C-2/1 lithium-ion battery test show that discharge capacity rise to 800 mAhg-1 and coulombic efficiency is nearly 100% during 500 cycles for LIBs.NiO@Ni@C-1/1 shows that discharge capacity can maintain 350 mAhg-1 and coulombic efficiency is nearly 100% during 500 cycles for LIBs.NiO@Ni@C-1/2 can maintain 160 mAhg-1 and coulombic efficiency is nearly 100% during 1000 cycles for LIBs.Used NiO@Ni@C-2/1 for oxygen reduction?ORR?,oxygen evolution?OER?dual catalytic and zinc air battery test.NiO@ Ni@C-2/1 exhibits good OER activity,the maximum activity of 10 mAcm-2 overcurrent is 380 mV,the current density at 1.8 V is 114 mAcm-2.In the ORR test,the initial potential,half-wave potential and ultimate diffusion current density at 1600 rpm were 0.87 V,0.7 V and 4.6 mAcm-2,respectively.Zinc air battery test,NiO@Ni@C-2/1 of the initial charge and discharge voltage of 0.8 V,resulting in a voltage efficiency of 39%.50 hours after 50 cycles,the potential of charge and discharge rise to 0.85 V.