Lithium Storage in Nanoporous Complex Oxide 12CaO•7Al2O3 (C12A7)

Abstract

Porous materials have generated a great deal of interest for use in energy storage technologies, as their architectures have high surface areas due to their porous nature. They are promising candidates for use in many fields such as gas storage, metal storage, gas separation, sensing and magnetism. Novel porous materials which are non-toxic, cheap and have high storage capacities are actively considered for the storage of Li ions in Li-ion batteries. In this study, we employed density functional theory simulations to examine the encapsulation of lithium in both stoichiometric and electride forms of C12A7. This study shows that in both forms of C12A7, Li atoms are thermodynamically stable when compared with isolated gas-phase atoms. Lithium encapsulation through the stoichiometric form (C12A7:O2−) turns its insulating nature metallic and introduces Li+ ions in the lattice. The resulting compound may be of interest as an electrode material for use in Li-ion batteries, as it possesses a metallic character and consists of Li+ ions. The electride form (C12A7:e−) retains its metallic character upon encapsulation, but the concentration of electrons increases in the lattice along with the formation of Li+ ions. The promising features of this material can be tested by performing intercalation experiments in order to determine its applicability in Li-ion batteries.

[Ca24Al28O64]4+(4e−) are directly and quickly synthesized by self‐reduction of C12H10Ca3O14 + Al2O3 without any reducing agent

“…[Ca 24 Al 28 O 64 ] 4+ (4e − ) electrides (C12A7:e − ) is a conductive oxide ceramic with high carrier density and low work function 1–3 . Its unit cell structure is shown in Figure 1, its lattice constant is 11.95 Å, 4,5 and it is a simple cubic crystal structure composed of Ca, Al, and O elements 1,6 . The unit cell is composed of a positive electric framework [Ca 24 Al 28 O 64 ] 4+ formed by 12 sub‐nanometer cages and 4e − bounded inside the cage, and these cages are coplanar connected 7–9 .…”