Open circuit voltage profile for Li-intercalation in rutile and anatase from first principles

2002 ◽  
Vol 152-153 ◽  
pp. 189-194 ◽  
Author(s):  
M Koudriachova
2002 ◽  
Vol 756 ◽  
Author(s):  
Marina V. Koudriachova ◽  
Simon W. de Leeuw

The effect of substitution on the intercalation properties of anatase-structured titania has been investigated in first principles calculations. Ti4+-ions were substituted by Zr4+, Al3+ and Sc3+ respectively and O2- -ions by N3-. For each compound the open circuit voltage profile (OCV) was calculated and compared to anatase. Lithium intercalation proceeds as in pure anatase through a phase separation into a Li-rich and a Li-poor phase in all cases examined here. The Li-content of the phases depends on the nature of the dopant and its concentration. Substitution by N3--ions does not lead to lower potentials, whereas doping with trivalent Sc3+- and Al3+- ions decreases the intercalation voltage. Substitution by tetravalent Zr4+-ions within the range of solubility does not significantly affect the OCV of anatase. A correlation is observed between the predicted equilibrium voltage and the participation of the Ti4+-ions in accommodating the donated electron density upon lithiation.


2021 ◽  
Vol 896 ◽  
pp. 53-59
Author(s):  
Yi Yang Shen

The development of next generation Li ion battery has attracted many attentions of researchers due to the rapidly increasing demands to portable energy storage devices. General Li metal/alloy anodes are confronted with challenges of dendritic crystal formation and slow charge/discharge rate. Recently, the prosperity of two-dimensional materials opens a new window for the design of battery anode. In the present study, MoS2/graphene heterostructure is investigate for the anode application of Li ion battery using first-principles calculations. The Li binding energy, open-circuit voltage, and electronic band structures are acquired for various Li concentrations. We found the open-circuit voltage decreases from ~2.28 to ~0.4 V for concentration from 0 to 1. Density of states show the electrical conductivity of the intercalated heterostructures can be significantly enhanced. The charge density differences are used to explain the variations of voltage and density of states. Last, ~0.43 eV diffusion energy barrier of Li implies the possible fast charge/discharge rate. Our study indicate MoS2/graphene heterostructure is promising material as Li ion battery anode.


2016 ◽  
Vol 4 (16) ◽  
pp. 6029-6035 ◽  
Author(s):  
Deniz Çakır ◽  
Cem Sevik ◽  
Oğuz Gülseren ◽  
Francois M. Peeters

Its good electrical conductivity, fast ion diffusion, good average open-circuit voltage and theoretical capacity suggest that the Mo2C monolayer can be utilized as a promising anode material.


2021 ◽  
Vol 58 (6) ◽  
pp. 13-23
Author(s):  
D. Sergeyev ◽  
N. Zhanturina ◽  
A. Aizharikov ◽  
A.I. Popov

Abstract The study focuses on the optical properties of the CZTS multicomponent semiconductor absorber with 3 % “production” impurities of Cd, Na, O within the framework of the density functional theory using the generalized gradient approximation and the SCAPS program, as well as investigates their influence on the performance and efficiency of CZTS-solar cells. The results showed that the introduction of Cd, Na, O impurities would lead to a decrease in the intensity of the absorption bands at 2.06 eV and 2.55 eV. The density of states CZTS: (Cd, Na, O) was determined from first principles, and it was revealed that impurities of Cd and O atoms would lead to a decrease in the band gap (to 0.9 eV and 0.79 eV), and an increase in Na impurity absorption (1.2 eV). It was also found that a decrease in the band gap led to a decrease in the open circuit voltage, and it was also shown that “industrial” impurities led to a decrease in the efficiency of energy conversion of solar cells to 2.34 %.


2003 ◽  
Vol 762 ◽  
Author(s):  
Jianhua Zhu ◽  
Vikram L. Dalal

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.


Author(s):  
Pietro Caprioglio ◽  
Fengshuo Zu ◽  
Christian M. Wolff ◽  
Martin Stolterfhot ◽  
Norbert Koch ◽  
...  

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