Continuum and atomistic models of strongly coupled diffusion, stress, and solute concentration

• Published in: Journal of power sources Vol. 196; no. 1; pp. 361 - 370
• Main Authors: Haftbaradaran, Hamed, Song, Jun, Curtin, W.A., Gao, Huajian
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2011; Elsevier
• Subjects: Activation energy; Applied sciences; Atomistic simulations; Binding energy; Computer simulation; Continuums; Diffusion; Diffusion-induced stress; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrodes; Exact sciences and technology; Modulus of elasticity; Nickel; Stoichiometric limit; Stress concentration; Stresses; Diffusion-induced stress; Atomistic simulations; Activation energy; Binding energy; Stoichiometric limit; Lithium battery; Parametric method; Stress concentration; Concentration effect; Stress effects; System simulation; Diffusion
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2010.06.080

Poor cyclic performance of electrodes in lithium-ion rechargeable cell batteries is calling for efforts to develop continuum models of diffusion under very large stresses and high solute concentrations. The present work is aimed to develop such a model based on input from atomistic simulations. We consider four fundamental features of highly nonlinear behavior associated with diffusion at high solute concentrations. First, the effect of solute-induced stresses on the activation energy of solute diffusion could be important. Second, the solute concentration may be subject to an upper limit if there exists a stoichiometric maximum concentration. Third, the strong influence of the change in local chemical environment on the interaction energy between solute and host atoms could play a significant role. Fourth, we include the effect of the solute concentration on the Young's modulus of the host material. A continuum model is developed and validated based on atomistic simulations of hydrogen diffusion in nickel. The influences of each feature above are clearly discussed through parametric studies.