Influence of elastic strain on the thermodynamics and kinetics of lithium vacancy in bulkLiCoO2

Abstract

The influence of elastic strain on the lithium vacancy formation and migration in bulk LiCoO 2 is evaluated by means of first-principles calculations within density functional theory (DFT). Strain dependent energies are determined directly from defective cells and also within linear elasticity theory from the elastic dipole tensor (G i j ) for ground state and saddle point configurations. We analyze finite size-effects in the calculation of G i j , compare the predictions of the linear elastic model with those obtained from direct calculations of defective cells under strain and discuss the differences. Based on our data, we calculate the variations in vacancy concentration and mobility due to the presence of external strain in bulk LiCoO 2 cathodes. Our results reveal that elastic in-plane and out-of-plane strains can significantly change the ionic conductivity of bulk LiCoO 2 by an order of magnitude and thus strongly affect the performance of Li-secondary batteries.

Quantum prediction of ultra-low thermal conductivity in lithium intercalation materials

“…During the charging/discharging process, large strains can be accumulated 5,41,42 , with LixCoO2 being able to sustain as large as 30% through-plane strain 43 . The strain impact on the mechanical, electrical, and ionic transport properties have been extensively studied [43][44][45][46] , while the impact on thermal transport is still unclear. Taking delithiated LixCoO2 (x=0.…”

A three-dimensional finite element formulation coupling electrochemistry and solid mechanics on resolved microstructures of all-solid-state lithium-ion batteries

“…This information can be utilized in multiple ways, e.g. to evaluate whether mechanical failure mechanisms are likely to occur or to add further coupling effects like deformation dependent electrochemical transport properties as deduced from detailed atomistic simulations in [68].…”

“…The most obvious effect in this regard is the delamination of active materials and solid electrolyte. But also the dependence of the electrochemical transport kinetics on the mechanical deformation state as proposed by [68] will be an important step to enable the quantification of this effect deduced on an atomistic scale on the electrochemical performance on the cell level. Moreover, we believe that the incorporation of inhomogeneous lithium deposition and stripping at the lithium metal anode, and grain boundary transport mechanisms on resolved solid electrolyte grains are other effects of particular importance.…”

Interfacial strain effects on lithium diffusion pathways in the spinel solid electrolyte Li-doped MgAl2O4

“…The effect of interfacial strain on ionic conductivities has been widely studied in fuel cell materials [20][21][22][23][24][25][26][27], motivated by the possibility of straining thin-film electrolytes to enhance their oxide-ion conductivities, and hence reduce device operating temperatures. More recently, the concept of "strain engineering" has also been considered as a strategy for enhancing lithium conductivity in lithium-ion electrodes and electrolytes [28][29][30][31][32][33][34][35][36][37]. The effect of interfacial strain is particularly pertinent for an electrolyte such as (Li,Al)-codoped MgAl 2 O 4 , where interest is motivated by the possibility of lattice matching with spinel-structured electrolytes.…”