Phosphates as Lithium-Ion Battery Cathodes: An Evaluation Based on High-Throughput ab Initio Calculations

Abstract

Phosphate materials are being extensively studied as lithium-ion battery electrodes. In this work, we present a highthroughput ab initio analysis of phosphates as cathode materials. Capacity, voltage, specific energy, energy density, and thermal stability are evaluated computationally on thousands of compounds. The limits in terms of gravimetric and volumetric capacity inherent to the phosphate chemistry are determined. Voltage ranges for all redox couples in phosphates are provided, and the structural factors influencing the voltages are analyzed. We reinvestigate whether phosphate materials are inherently safe and find that, for the same oxidation state, oxygen release happens thermodynamically at lower temperature for phosphates than for oxides. These findings are used to recommend specific chemistries within the phosphate class and to show the intrinsic limits of certain materials of current interest (e.g., LiCoPO 4 and LiNiPO 4 ).

DFT investigation of the effect of spin-orbit coupling on the NMR shifts in paramagnetic solids

“…The latter method, which is widely used in periodic DFT calculations of transition metal-contain systems, is an alternative approach to the hybrid treatment and it involves the addition of a Hubbard U correction [59] to specific subshells -here the 3d TM orbitals -to correct for effects due to the incorrect treatment of electron correlations with the DFT approach [60]. This has previously been shown to improve the description of the magnetic coupling constants and the electronic structure of transition metal oxide systems [61][62][63][64], and to accurately predict the respective ground-state d-level splitting pattern [65]. The rotationally invariant treatment of U proposed by Dudarev et al was here used [66], in which a single U eff parameter is applied to the d electrons of the transition metal species.…”

Accuracy of density functional theory in predicting formation energies of ternary oxides from binary oxides and its implication on phase stability

“…[1][2][3][4][5][6][7][8] Reaction energies are also critical to the ab initio study of the thermodynamic stability of known materials [9][10][11][12][13][14] or the prediction of novel phases. [15][16][17][18][19][20][21][22][23][24][25][26][27] Indeed, it is a compound's energy relative to the energy from combinations of other phases, which determines its stability.…”

Layered Graphitic Carbon Host Formation during Liquid-free Solid State Growth of Metal Pyrophosphates

“…This was recently demonstrated by Tannenbaum et al 35 in the solid state preparation of metallic nanoparticles embedded in polymer. More recently, the pyrophosphates and phosphates which can result from the precursors by our method, have been investigated within the last year 36 as useful Li-ion battery materials and this approach augers well for the creation of a wide variety of transition metal-based pyrophosphates as tunnel-structure intercalation hosts for battery materials and energy storage. By this solid state approach, conductive layered, conductive graphitic carbon additives are formed in intimate contact with intercalation-possible inorganic (pyro)phosphate and oxide crystals directly on substrates; a one-step battery composite material without any liquid-based synthetic steps.…”