Fast lithium-ion conductivity in the ‘empty-perovskite’ n = 2 Ruddlesden–Popper-type oxysulphide Y₂Ti₂S₂O₅

Abstract

Materials with Wadsley-Roth (WR) crystallographic shear and bronze-type structures display fast lithium-ion diffusion and are of interest as anode materials for high-power Li-ion batteries. Here we use density-functional-theory calculations to...

Unveiling charge dynamics of visible light absorbing oxysulfide for efficient overall water splitting

“…The partial density of states computed using HSE06 hybrid functional (Supplementary Fig. 5) displays an energy band gap of 1.91 eV, which is well in agreement with the reported values of 1.9 eV (measured) 24 and 2.19 eV (DFT/HSE06 method) 34 . The slight discrepancy in the values of the band gap might be attributed to the difference in the basis sets.…”

“…Band structure calculation in Supplementary Fig. 4b reveals that Y 2 Ti 2 O 5 S 2 is a direct band-gap semiconductor, as pointed out previously 34 . The partial density of states computed using HSE06 hybrid functional (Supplementary Fig.…”

Energy storage mechanisms in vacancy-ordered Wadsley–Roth layered niobates

“…49,50 Diffusion of Na ions down square channels in WR and structurally related materials is limited by high activation barriers. 8,27 However, the dynamics of Na apparent in NMR of NaNb 3 O 8 , as well as the previously reported Na-ion storage in KNb 3 O 8 , 31 indicate that Na is mobile between the layers in these materials. Accordingly, WR-derived structures, such as the layered compounds studied here, may also be applicable hosts for other large cation species.…”

“…7,8 Because the WR framework structure does not change signicantly during lithiation, Li ions retain similar intercalation geometries across different states of charge that result in fast diffusion. 26,27 Motivated by their excellent anode properties, we investigated the electrochemical energy storage behavior of variations on the WR structure using complex niobates with layered and orderedcation-vacancy motifs (Fig. 1d-f).…”

Y2Ti2O5S2 – a promising n-type oxysulphide for thermoelectric applications

“…Y 2 Ti 2 O 5 S 2 has been studied as a potential battery anode but has also proven to be an excellent candidate for hydrogen production by photocatalytic water splitting. [21][22][23][24][25][26] The performance of the material in these applications stems from its uniquely complex structure, which renders it stable to Li intercalation and gives rise to relatively disperse electronic bands. The complex structure is also expected to facilitate strong phonon scattering and low lattice thermal conductivity, making Y 2 Ti 2 O 5 S 2 a promising thermoelectric candidate.…”