Research On The Application Of Nickel Based Alloy In The Cathode Material Of Lithium Sulfur Batteries

Lithium sulfur battery has become one of the most potential energy storage devices because of its high specific capacity and specific energy,as well as the abundant natural reserves of sulfur and its low cost.But sulfur is anything but an ideal material for an electrode.There are several key problems to be solved urgently:1)insulation of sulfur;2)shuttle effect caused by the movement of polysulfide between cathode and anode during battery operation.In this paper,nickel based alloy materials are introduced into the cathode material of lithium sulfur battery to accelerate the reaction kinetics of polysulfide conversion and inhibit the shuttle effect.The main contents of the article are as follows:?1?we designed a Li-S battery cathode having a three-dimensional?3D?network configuration composed of carbon nanotube?CNTs?,graphene?Gra?and S coupled with Al₃Ni₂?that is,CNTs/Gra-S-Al₃Ni₂?.It was anticipated that the 3D CNTs/Gra network and the introduction of Al in the form of Al₃Ni₂ would provide efficient channels for rapid electron and ion transfer,especially along the vertical direction of the cathode.The Ni in the Al₃Ni₂ is also able to rapidly eliminate accumulated LiPSs by increasing the rates of the LiPSs conversion reactions.As a result of the aforementioned merits,the optimized electrode generated a much higher initial discharge capacity of 1401 mA h g^-1 at a current of 0.2 C.This unit also exhibited an increased reversible capacity of 496 mA h g^-1 when cycled at 1 C over 800 cycles,with only a0.055%average capacity decay per cycle.Increasing the ASLs to 3.30 mg cm^-2 resulted in the electrode maintaining a high discharge capacity of622 mA h g^-1 after 200 cycles at a current density of 2.76 mA cm^-2,in conjunction with a high capacity retention of 85.9%.?2?After introducing the composite of carbon nanotube and the graph ene coupled with 5%FeCoNi alloy as sulfur host materials?CNTs/Gra-S-F eCoNi?,the CNTs/Gra-S-FeCoNi cathode delivered a reversible capacity of 437 mA h g^-1 over 800 cycles with an ultralow capacity degradation of0.061%per cycle at 1 C.When the ASLs are as high as 4.7 mg cm^-2,the battery displayed a high reversible areal capacity of 2.25 mA h cm^-2(479mA h g^-1)at a higher current density of 2.36 mA cm^-2 over 200 cycles in conjunction with a superior capacity retention of 75.6%.