Investigating Stability Properties for Transition Metal Carbonate Precursors Using Universal Cluster Expansion Technique(UNCLE)as Cathodes for Li-Ion Batteries

The universal cluster expansion technique was used in this study to determine the binary phase diagrams for the transition metal carbonate precursors MCO3(M:Mn,Ni,Co).The use of mixed cathode materials in lithium-ion batteries such as NMC(Ni,Mn and Co)formulations,is a strategic approach to optimize performance,enhance safety and address cost and environmental considerations in the rapidly evolving field of energy storage.This study focuses on the cost issue related to lithium ion batteries by investigating the manganese rich NMC since manganese is more abundant and cost-effective.We doped MnCO3 with nickel and doped MnCO3 with cobalt then ran cluster expansion calculations to generate binary phases.The binary phase diagrams generated indicated that doping MnCO3 with nickel favours the Mn-rich side,while doping MnCO3 with cobalt favours 50%Mn-rich and 50%Co-rich.We further extracted the most stable structures from both binary diagrams and determined their electronic,mechanical and vibrational stabilities using DFT(density functional theory)calculations within the LDA(local gradient approximation)with Hubbard parameter(U).The electronic properties revealed that both materials are semiconductors due to their narrow energy band gap obtained while the mechanical properties showed that structures are mechanically stable since their necessary conditions for trigonal and triclinic systems were satisfied.

Thermodynamic properties of 3C-SiC

In the present paper, we report on the results of various thermodynamic properties of 3C-SiC at high pressure and temperature using first principles calculations. We use the plane-wave pseudopotential density functional theory as im- plemented in Quantum ESPRESSO code for calculating various cohesive properties in ambient condition. Further, ionic motion at a finite temperature is taken into account using the quasiharmonic Debye model. The calculated thermody- namic properties, phonon dispersion curves, and phonon densities of states at different temperatures and structural phase transitions at high pressures are found to be in good agreement with experimental and other theoretical results.

Phonon dynamics of glassy copper alloys

The well recognized model potential is used to investigate the phonon properties for five glassy Copper alloys viz.Cu_(57)Zr_(43),Cu_(60)W_(40),Cu_(33)Y_(67),Cu_(43)Ti_(57) and Cu_(66)Ti_(34).The thermodynamic and elastic properties are also computed from the elastic limits of the phonon dispersion curves(PDC).Three theoretical approaches given by Hubbard-Beeby(HB),Takeno-Goda(TG)and Bhatia-Singh(BS)are used in the present study to compute the PDC.Five local field correction functions proposed by Hartree(H),Taylor(T),Ichimaru-Utsumi(IU),Farid et al.(F)and Sarkar et al.(S)are employed to see the effect of exchange and correlation in the aforesaid properties.

Vibrational dynamics of Fe-based glassy alloys

The well recognized model potential is used to investigate the vibrational properties of four Fe-based binary glassy alloys viz.Fe_(90)Zr_(10),Fe_(80)B_(20),Fe_(83)B_(17) and Fe_(80)P_(20).The thermodynamic and elastic properties are also computed from the elastic limits of the phonon dispersion curves(PDC).Three theoretical approaches given by Hubbard-Beeby(HB),Takeno-Goda(TG)and Bhatia-Singh(BS)are used in the present study to compute the PDC.Six local field correction functions proposed by Hartree(H),Taylor(T),Ichimaru-Utsumi(IU),Farid et al.(F)and Sarkar et al.(S)and Sarkar et al.’s local field factor(SLFF)based excgange and correlation function are employed to see the effect of exchange and correlation in the aforesaid properties.

Vibrational dynamics of Ni-glassy alloys

The well known model potential is used to investigate the vibrational properties of some Ni-based binary glassy alloys using three theoretical models.Different local field correction functions are employed to see the effect of exchange and correlation in the aforesaid properties and have been found successful.