Insertion of Mono- vs. Bi- vs. Trivalent Atoms in Prospective Active Electrode Materials for Electrochemical Batteries: An ab Initio Perspective

Abstract

Rational design of active electrode materials is important for the development of advanced lithium and post-lithium batteries. Ab initio modeling can provide mechanistic understanding of the performance of prospective materials and guide design. We review our recent comparative ab initio studies of lithium, sodium, potassium, magnesium, and aluminum interactions with different phases of several actively experimentally studied electrode materials, including monoelemental materials carbon, silicon, tin, and germanium, oxides TiO 2 and V x O y as well as sulphur-based spinels MS 2 (M = transition metal). These studies are unique in that they provided reliable comparisons, i.e., at the same level of theory and using the same computational parameters, among different materials and among Li, Na, K, Mg, and Al. Specifically, insertion energetics (related to the electrode voltage) and diffusion barriers (related to rate capability), as well as phononic effects, are compared. These studies facilitate identification of phases most suitable as anode or cathode for different types of batteries. We highlight the possibility of increasing the voltage, or enabling electrochemical activity, by amorphization and p-doping, of rational choice of phases of oxides to maximize the insertion potential of Li, Na, K, Mg, Al, as well as of rational choice of the optimum sulfur-based spinel for Mg and Al insertion, based on ab initio calculations. Some methodological issues are also addressed, including construction of effective localized basis sets, applications of Hubbard correction, generation of amorphous structures, and the use of a posteriori dispersion corrections.

Data-driven kinetic energy density fitting for orbital-free DFT: Linear vs Gaussian process regression

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Can doping of transition metal oxide cathode materials increase achievable voltages with multivalent metals?

“…To compare the effect of substitutional doping, insertion/adsorption voltages were used as a central performance metric. Neglecting entropic contributions and pressure‐volume work for reactions in the solid state in Equation ), as commonly done in the ab initio literature [ 37,38 ] on electrode materials, average voltages V can be approximated as change in static DFT energy E per transferred charge …”

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