Alkali Ion Transport in Tavorite-Type ABTO4X (A: Li, Na; B-T: Al-P, Mg-S; X: F)

Abstract

The promise of high safety and stability in solid-type electrolytes has prompted many battery researchers to find candidate inorganic compounds to replace existing liquid/polymer-based electrolytes. In this report, the alkali ion transport in tavorite-type ABTO 4 X (A: Li, Na; B-T: Al-P, Mg-S; X: F) is investigated by ab initio calculation, bond valence path approach, and void space analysis in order to explore their viability as solid electrolytes for all-solid state Li/Na ion batteries. Results from nudged elastic band and bond valence pathway methods reveal that the Li analogues are capable of 1D Li ion diffusion (<0.60 eV) characterized by a zigzag pathway along c-axis and passing between BO 4 F 2 pairs at each intersite jumps. However, the Na analogues show poor ionic conduction as evidenced by the relatively higher Na migration energy (>0.80 eV) for the same pathway due the larger size of the Na ion and the unchanged critical size along the conduction channel.

Density Functional Theory Investigation of Mixed Transition Metals in Olivine and Tavorite Cathode Materials for Li-Ion Batteries

“…These values are also worthy of consideration for practical battery applications. , The reduced migration energy values for both structures may be attributed to the different repulsive Li–Me (Me = Mn, Ni) and Me–Me interactions . The predicted migration energy values are also comparable to these of practical battery materials, for example, LiFePO 4 (0.41 eV), LiFe 0.875 Mn 0.125 PO 4 (0.67 eV), VOPO 4 (0.46 eV), LiAlPO 4 F (0.55 eV), LiMn 0.875 Fe 0.125 PO 4 (0.66 eV), LiVPO 4 F (0.4 eV), and LiNi 0.5 Co 0.2 Mn 0.3 O 0.2 (0.5 eV). − …”

High-Throughput Screening of Solid-State Li-Ion Conductors Using Lattice-Dynamics Descriptors

“…To further employ this understanding of the influence of lattice dynamics on ion mobility, in this article, we present the result of a high-throughput (HT) study of more than 1,000 Li-containing compounds using a lattice dynamic descriptor called the lithium-phonon band center, which is a measure of the average vibrational frequency of the lithium sublattice and has been proposed as a descriptor for the migration barrier or enthalpy of migration of lithium conductors in LISICON and olivine families (Muy et al, 2018b), in addition to several correlations between electronic structures, lattice dynamics, migration barrier, and electrochemical stability (Figure 1). Previous HT studies employed descriptors that were designed essentially based on static structural features (Avdeev et al, 2012;Wang et al, 2015) or using machine learning techniques to capture underlying correlations between the input features and the target properties from a database (Jalem et al, 2013;Sendek et al, 2018Sendek et al, , 2017. For instance, Wang et al (Wang et al, 2015) have proposed that a body-center cubic (BCC) structure provides the ideal framework for Li-ion conduction, where the deviation from the ideal BCC structure can be used as a descriptor for faster Li-ion conductors.…”

First-Principles Investigation of the Na+ Ion Transport Property in Oxyfluorinated Titanium(IV) Phosphate Na3Ti2P2O10F

“…One example is Na + ion batteries which can offer a potential cost advantage because of the almost inexhaustible supply of Na. Another interesting point is the similarity between Na and Li intercalation chemistry which allows for similar compounds to be used, in both battery types. , Generally though, the relatively larger Na + ion (vs Li + ion) is often viewed to pose a problem for ionic conduction. − However, several Na-based materials have been reported already to demonstrate good or even better ionic mobility (than their Li counterpart), facilitated by the large enough tunnels and void spaces in a variety of structures. − High-voltage novel cathodes, such as Na 3 V 2 O 2 x (PO 4 ) 2 F 3–2 x and Na 2 Fe 2 (SO 4 ) 3 , have been developed as well that address the issue of lower energy density in Na-based systems stemming from the higher reduction potential of Na metal (−2.7 V vs standard hydrogen electrode or SHE for Na as compared to −3.0 V vs SHE for Li) and the higher equivalent weight of Na (vs Li). , Recently, safety enhancement of Li/Na batteries has been pursued by substituting conventional organic-/liquid-based electrolytes with inorganic or solid-based ones. Up to date, NASICON-type (Na Super Ionic CONductor) compounds − and Na β″-alumina − are considered as among the few that show promise for solid electrolyte use.…”