Communication—Investigation of Anatase-TiO₂as an Efficient Electrode Material for Magnesium-Ion Batteries

Abstract

Magnesium-ion batteries (MIBs) have twofold volumetric energy density than that of lithium without the dendritic deposition morphology associated with Li, which makes MIBs attractive options. We investigate the feasibility of using anatase-phase TiO 2 as an electrode material for MIBs. Electrochemical, microscopic, and spectroscopic analyses are performed in order to probe Mg-ion insertion as well as determine the limitation of TiO 2 as a viable electrode material.

Mg Cathode Materials and Electrolytes for Rechargeable Mg Batteries: A Review

“…Most of these transition metal compounds are nanosized, to provide a high surface area with more active sites for cation intercalation as well as short ion-transport paths to facilitate cation diffusion. [44,114] However, with their high charge density, Mg 2 + ions are restricted by their strong electrostatic interaction with the electron-rich oxygen centres, and become trapped in the solid-state lattice. [94][95]97,99,115] The cyclability and cycling efficiency of these cathode materials are typically not high, due to the highly irreversible Mg intercalation behaviour.…”

“…Studies on transition-metal oxide cathodes with various Mg dual-salt electrolytes (containing both Mg and Li/Na salts) have thus been reported. [111,113,[118][119][120][121][122][123][124][125][126] Compared to Mg salts, the monovalent property of Li and Na salts means that they have weaker electrostatic interactions and lower co-ordination numbers, making them more soluble in the solvents. For instance, [119] LiNTf 2 showed a higher solubility in diglyme than that of Mg[NTf 2 ] 2 Highly reversible charge-discharge behaviour is observed in some of these Mg hybrid systems, with reasonable output voltage and energy capacity.…”

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

“…Some of these studies considered for the first time phononic effects on lithiation, sodiation, and magnesiation, and effects on voltage of doping. While most of these studies helped explain the mechanism and parameters of performance which had already been observed experimentally, some of them predicted electrochemical activity before it was confirmed experimentally, for example, the recently confirmed sodiation of amorphous silicon [20,38] or voltages achieved with magnesiated TiO 2 [22,39]. Some of the calculations we performed and review below still await experimental confirmation such as our prediction of significantly enhanced insertion energetics by p-doping.…”

“…We have produced the first comparative computational study [22] of Li, Na, and Mg interaction with four phases of titania which are intensely studied by experimentalists as potential electrode materials: anatase, rutile, (B), and amorphous TiO 2 [39,[100][101][102][103][104][105][106][107][108][109][110][111][112]. Interaction energies were mapped for the first time among the three types of inserted metal atoms and four phases.…”

“…Titanium dioxide is by far the most prominent oxide that found use in multiple electrochemical power generation and storage technologies such as solar cells (dye-sensitized and sensitized-type perovskite) and batteries (including post-lithium batteries considered here) as well as in photocatalysis for environmental remediation and water splitting [39,[101][102][103][104][105][106][107]110,112]. The understanding of the mechanism of operation of all these technologies critically depends on the understanding of the electronic structure of TiO 2 .…”