The Effect of Stress on Battery-Electrode Capacity

TitleThe Effect of Stress on Battery-Electrode Capacity
Publication TypeJournal Article
Year of Publication2017
AuthorsBucci, G, Swamy, T, Bishop, S, Sheldon, BW, Chiang, YM, Carter, WCraig
JournalJournal of the Electrochemical Society
PaginationA645 - A654
Date Published2017///
ISBN Number0013-4651
Keywordsanodes, fracture, li-batteries, lithiation, lithium-ion battery, si nanoparticles, silicon, solid-state batteries, thermochemical equilibrium, thin-film electrodes

Constraint-induced stresses develop during Li-ion battery cycling, because anode and cathode materials expand and contract as they intercalate or de-intercalate Li. We show in this manuscript that these stresses, in turn, can significantly modify the maximum capacity of the device at a given cell voltage. All-solid-state batteries impose an external elastic constraint on electrode particles, promoting the development of large stresses during cycling. We employ an analytic and a finite element model to study this problem, and we predict that the electrode's capacity decreases with increasing matrix stiffness. In the case of lithiation of a silicon composite electrode, we calculate 64% of capacity loss for stresses up to 2 GPa. According to our analysis, increasing the volume ratio of Si beyond 25-30% has the effect of decreasing the total capacity, because of the interaction between neighboring particles. The stress-induced voltage shift depends on the chemical expansion of the active material and on the constraint-induced stress. However, even small voltage changes may result in very large capacity shift if the material is characterized by a nearly flat open-circuit potential curve. (C) 2017 The Electrochemical Society. All rights reserved.

Short TitleJ. Electrochem. Soc.