Dilithium ethylene dicarbonate (Li2EDC) and dilithium butylene dicarbonate (Li2BDC) are the common organic compositions of the solid electrolyte interphase (SEI) layers in rechargeable lithium-ion batteries. The Li+ diffusion in the amorphous and ordered phases of Li2EDC and Li2BDC under various strains have been investigated using molecular dynamics simulations. It is found that different strains lead to diverse changes in Li+ diffusivity. The tensile strain makes the Li+ diffusion coefficients increase in amorphous and ordered Li2EDC or Li2BDC, and the compressive strain makes the Li+ diffusion coefficients decrease in them. The average Li+ coordination number calculation, ion conductivity calculation and the calculation of the residence autocorrelation function in amorphous and ordered Li2EDC or Li2BDC are performed to further analyze the strain effects on Li+ transport in them. The factors influencing Li+ diffusion in amorphous and ordered Li2EDC or Li2BDC under the strain are discussed.

The interaction between mechanics and chemistry plays an essential and critical role in the surface segregation and relaxation in nanoscale alloys. Following the thermodynamics analysis based on surface eigenstress, the present study takes the free-standing nanometer thick films of Ni1 –x Cux solid solutions with face-centered cubic (fcc) crystalline structures as an example to investigate surface segregation of Cu and relaxation of the films. Hybrid Monte Carlo and Molecular Dynamics (MCMD) simulations are conducted on free-standing Ni1 –x Cux alloys of (100) and (111) nanofilms. The MCMD simulations verify the theoretical analytic results and determine the values of parameters involved in the theoretical analysis. Especially, the parameter of the differentiation in reference chemical potential behaves like the molar free energy of segregation in the McLean adsorption isotherm, and the differentiation in chemical composition induced eigenstrain plays also an important role in surface segregation and relaxation. The integrated theoretical and numerical study exhibits that both surface excess Cu concentration and apparent biaxial Young's modulus of Ni1 –x Cux nanofilms depend on the nominal Cu concentration and the film thickness.