TiS₃ Magnesium Battery Material: Atomic-Scale Study of Maximum Capacity and Structural Behavior

Abstract

Good cyclability is essential for the potential application of cathode materials. We investigated electrochemical properties of Mg in layered intercalation compound from first-principles using TiS3 as a model system. The calculations showed exothermic phase transformation upon intercalation of Mg from the electrolyte: the geometry optimization of the structure containing 0.5 Mg showed the shift of layers accompanied by change of Mg coordination from square pyramidal to trigonal prismatic. Further increase of the Mg content leads to break of the S–S bonds in the disulfide ion and conversion of the TiS3 layers into ribbons. The obtained phase is metastable and can easily and irreversibly decompose to MgS and TiS2. This means that in order to achieve full theoretical capacity of TiS3 this decomposition has to be suppressed. A very low migration barrier of 0.292–0.698 eV (depending on the Mg content) was found in the [010] direction, which is much lower than the value of analogues, such as layered and spinel TiS2. This finding reveals the potential of TiS3 to become Mg cathode with superior performance compared to similar analogues.

Exfoliation, point defects and hydrogen storage properties of monolayer TiS3: an ab initio study

“…This may indicate that the adsorption of sodium and especially lithium can be used to split the monolayer of TiS 3 into chains or substantially reduce the width of the nanobelts and needles. It can be seen that the increase of the Mg content absorbed by bulk TiS 3 leads to break of the S-S bonds in the disulde ion and conversion of similar effect was found in our recent work 55 when it was found the TiS 3 layers into ribbons. It should be noted that the creation of single vacancy induces the same separation effect as Li/Na adsorption (parameter a increases to 10.379Å, see Table 3), however, for the case of two vacancies per the 2 Â 3 Â 1 supercell, this effect disappears quickly.…”

“…52 Bulk TiS 3 proved to be promising as a cathode material for lithium, sodium, and magnesium batteries. [52][53][54][55] The creation of sulfur vacancies in transition metal sulphides is an effective way of increasing their catalytic activity, as shown, for example, in the work on MoS 2 . 56 This could make TiS 3 reactive towards hydrogen adsorption through the creation of more active sites.…”

Recent Progress on Layered Cathode Materials for Nonaqueous Rechargeable Magnesium Batteries

“…[76,77] The migration barrier for Recently, the insertion mechanism of Mg 2+ in TiS 3 was investigated by first-principles calculations. [76] After 0. However, the microsized TiS 3 exhibits poor electrochemical performance.…”

Anionic Redox Chemistry in Polysulfide Electrode Materials for Rechargeable Batteries

“…Transition‐metal trichalcogenides with quasi‐layered structures (Figure d) NbSe 3 , TiS 3 , and other MQ 3 (M=Zr, Hf, Nb, Ta; Q=S, Se) were tested as cathodes of LIBs in early works and recently revisited in experimental (TiS 3 , Li 2 TiS 3 , Li 3 NbS 4 ) and theoretical works (TiS 3 ) . MQ 3 are able to host several Li atoms, as may be seen with the example of TiS 3 : …”

“…The theoretical capacity of the TiS 3 electrode is 558 mAhg −1 , and a high capacity of 350 mA h g −1 is realized in the first five cycles. Recent DFT calculations on TiS 3 electrodes for Li‐, Na‐, and Mg‐ion batteries revealed a significant charge transfer between the adsorbed metal and its nearest S atoms (Figure a). In fact, our early experimental studies on Li intercalation into other trichalcogenides, NbS 3 and NbSe 3 , agree with this finding.…”