Preparation and Structure of Lithium‐Ion‐Conducting Mixed‐Anion Glasses in the System LiBO₂–LiBS₂

Abstract

Oxysulfide glasses were prepared in a wide range of compositions in the system LiBO2‐LiBS2. Temperatures of glass transition (Tg), crystallization (Tc), and liquidus (Tl) were determined; a maximum of Tg was observed near the composition with 20 mol% LiBS2. The electrical conductivity at 500 K ranges from 5×10−4 to 5×10−3 S·cm−1 with the maxima in conductivity observed near the composition 55LiBO2·45LiBS2. This conductivity enhancement with a mixing of two components, which can be called the mixed‐anion effect, is accompanied by a decrease in the degree of undercooling of glass expressed by the ratio (Tl‐Tg)/Tl. The infrared and Raman spectra showed that the structural units with bridging oxygens B‐O‐B and nonbridging sulfurs B‐S− predominated rather than those with nonbridging oxygens B‐O− and bridging sulfurs B‐S‐B in these glasses.

Effect of VO43−Substitution for PO43−on Electrical Conductivity in the Nasicon Li3Sc2(PO4)3Compound

“…For some materials, such as Li 4 SiO 4 -Li 3 BO 4 glasses, the improved conductivity was resulted from the aliovalent ion substitution [14] and was explained by the charge compensation mechanism. For materials, such as in LiBO 2 -LiBS 2 glasses [13] and AgBr-AgI mixed crystals, the enhanced conductivity was originated from homovalent ion replacement [33] and the effect of size, polarizability of the substituted homovalent ions should be responsible for the improved conductivity.…”

“…Kim et al [32] and Minami et al [13,34] proposed some favorable diffusion paths for ion transport in the 0.5Li 2 S-0.5[(1Àx) GeS 2 +xGeO 2 ], e.g. having oxygen at bridging positions in mixed Ge-(S/O) 4 tetrahedra and sulfur at both bridging and non-bridging positions due to the replacement of sulfur by oxygen.…”

“…Electrical conductivity of solid state electrolytes, such as glasses and crystalline materials, can be effectively enhanced by the socalled mixed anion effect [13][14][15][16][17][18][19][20][21]32,33]. For some materials, such as Li 4 SiO 4 -Li 3 BO 4 glasses, the improved conductivity was resulted from the aliovalent ion substitution [14] and was explained by the charge compensation mechanism.…”

“…It is well known that the so called "mixed anion effect" plays an important role in improving the ionic conductivity of silver and lithium ion-conducting glasses [13][14][15][16]. Studies on the Li 1 +x Al x Ti 2Àx (PO 4 ) 3 compound have shown that VO 4 3À anion substitution for PO 4 3À can improved the sinterability of the material, and consequently its ionic conductivity [17][18][19][20][21].…”

Development of sodium ion conducting mixed anion glassy solid-state electrolytes

“…Mixed oxy-sulfide materials have slowly gained traction since their discovery in the 1980s 62,[128][129][130][131][132][133][134] . Efforts were made to improve the ionic conductivity of oxide glasses by increasing the polarizability of the anions to facilitate ion transport [134][135][136][137] .…”