Abstract
The ternary cathode material LiNi1/3Co1/3Mn1/3O2 has been extensively focused on as the power sources for new electro-optical conversion devices and lithium-ion batteries. To improve the electrochemical performance, Al doping is one of the effective strategies. Based on the density functional theory of first-principles, the band gap, volume, partial density of states, lithiation formation energy, electron density difference, and electrons’ potential energy of Li1.0-xAlxNi1/3Co1/3Mn1/3O2 were simulated and analyzed with Materials Studio, Nanodcal and Matlab. Results show that Li0.9Al0.1Ni1/3Co1/3Mn1/3O2 has a better conductivity and cycling capability. The potential energy maps of Li1.0-xAlxNi1/3Co1/3Mn1/3O2 simulated in Matlab indicate that the rate capability of LiNi1/3Co1/3Mn1/3O2 is promoted after Al doping. Our theoretical advice could be an important choice for the power application of new optoelectronic devices. In addition, our methods could provide some theoretical guidance for the subsequent electrochemical performance investigations on doping of optoelectronic devices or lithium-ion battery materials.
Highlights
In recent years, rechargeable lithium-ion batteries (LIBs) are the leading power sources for new electro-optical conversion devices, portable electronic devices, electric vehicles and hybrid electric vehicles for their less pollution, good cycle property, no memory effect, high energy density, and high specific capacity at high voltage (4.5 V) [1]
Our findings can give some theoretical advice about studies of the power module for new electro-optical conversion devices and investigations on LIBs; methods we presented can shorten greatly the whole period of experiments or investigations and reduce the experimental cost [26]
After Al doping, Li1.0-xAlxNi1/3Co1/3Mn1/3O2 has a layered structural stability when x < 0.12 mol; the band gap has a minimum at x 0.11 mol, and the conductivity is best; the peak of partial density of state (PDOS) remains highly within x 0.06–0.10 mol, which electrons are multiplied than the pristine, and its conductivity is enhanced dramatically; the lithiation formation energy E is lowest at x 0.11 mol, and electrons and Li-ions can be separated within x < 0.12 mol; based on the simulations of the electron density difference, Li1.0-xAlxNi1/3Co1/3Mn1/3O2 has a better conductivity when x 0.08 – 0.10 mol; and electrons’ potential barrier is decreasing with rising x, electrons and Liions can be removed and diffused quickly, which means its rate capability is improved effectively
Summary
Rechargeable lithium-ion batteries (LIBs) are the leading power sources for new electro-optical conversion devices, portable electronic devices, electric vehicles and hybrid electric vehicles for their less pollution, good cycle property, no memory effect, high energy density, and high specific capacity at high voltage (4.5 V) [1]. The specific capacity of commercial cathode materials of LIBs is far lower than that of the anode. It is a major challenge to pursuit the appropriate cathode material for the power module of electro-optical conversion devices or LIBs. Nowadays, the layered ternary lithium nickel-cobalt-manganese oxide has been well studied and widely applied into LIBs and the power module of optoelectronic devices for their lower price, good cycle performance and high thermal stability [2]. Among various ternary cathode materials, LiNi1/3Co1/3Mn1/3O2, whose structure likes LiCoO2 with α-NaFeO2-type, is extensively investigated owing
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