Improved Electrochemical Performance Of NiO Based Nanocomposites As Anode Materials For Lithium Ion Batteries

The main content of the present research is to improve the initial coulombic efficiency and the cycling performance of NiO as an anode material for lithium ion batteries by means of preparing NiO based nanocomposites.Exactly,NiO/Ni,Li_0.68Ni_1.32O₂/Ag,net-structured NiO/C,spherical porous NiO/C,nickel foam-supported porous NiO/Ag spheres,nickel foam-supported net-structured NiO/Ag film,and nickel foam-supported net-structured NiO/PANI film were prepared.NiO/Ni nanocomposite was prepared by calcination.Because the Ni nanoparticles promote the first charge reaction to a higher extent and also enhance the conductivity,the initial coulombic efficiency of NiO/Ni nanocomposite is 71%,higher than that of pure NiO (65%),and its specific capacity after 50 cycles at the current density of 100 mA g^-1 is 640 mAh g^-1,also higher than that of NiO(360 mAh g^-1).Li_0.68Ni_1.32O₂/Ag nanocomposite was prepared by a solid state reaction and an Ag-plating process.More Li₂O results in a higher reaction extent of the first charge reaction,so the initial coulombic efficiency of Li_0.68Ni_1.32O₂ is 73%,higher than that of NiO(65%),but its specific capacity after 40 cycles at the current density of 100 mA g^-1 is only 360 mAh g^-1.For Li_0.68Ni_1.32O₂/Ag nanocomposite,as Ag enhanced the conductivity,its initial coulombic efficiency is 72%,and the capacity after 40 cycles at the same current density is 570 mAh g^-1.Net-structured NiO/C nanocomposite was prepared by homogeneous precipitation, calcination and hydrothermal processes.The net-structured NiO exhibits higher capacities at 0.1,0.5 and 1 C,compared with granular NiO.Its capacity after 40 cycles at the current density of 0.1 C is only 180 mAh g^-1,but for NiO/C nanocomposite,because of its better conductivity and structural stability,this capacity is up to 430 mAh g^-1.Spherical porous NiO/C nanocomposite was prepared by calcination and hydrothermal processes.The spherical porous NiO/C exhibits higher capacities at high current densities, compared with spherical porous NiO,and its specific capacity after 40 cycles at the current density of 0.5 C is 430 mAh g^-1,higher than that of spherical porous NiO(200 mAh g^-1), which is attributed to the enhanced conductivity by carbon.Nickel foam-supported porous NiO/Ag spheres were prepared by electrodeposition, calcination and Ag-plating.By forming composite with the highly conductive Ag nanoparticles,the initial coulombic efficiency is increased from 48%to 59%,and the specific capacity after 40 cycles at the current density of 100 mA g^-1 is increased from 290 mAh g^-1 to 490 mAh g^-1.Nickel foam-supported net-like NiO was prepared by chemical bath deposition.NiO/Ag, NiO/PEDOT and NiO/PANI films were prepared by Ag-plating and electrodeposition.The initial coulombic efficiency of the net-like NiO film is 70%,and its specific capacities after 50 cycles are 490 mAh g^-1 and 350 mAh g^-1 at 0.5 A g^-1 and 1.5 A g^-1 respectively.For the NiO/Ag film,as Ag enhanced the conductivity,its specific capacities after 50 cycles are 550 mAh g^-1,450 mAh g^-1 and 420 mAh g^-1 at 0.5 A g^-1,1.5 A g^-1 and 3.0 A g^-1,respectively. For the NiO/PEDOT film,as the PEDOT enhanced the conductivity,its specific capacities after 50 cycles are 475 mAh g^-1 and 470 mAh g^-1 at 1 and 2 C,respectively.For the NiO/PANI film,as the PANI enhanced the conductivity and the stability of the net-like structure,its specific capacities after 50 cycles are 520 mAh g^-1 and 430 mAh g^-1 at 1 and 2 C.