Infrared spectroscopy of superionic conductor LiNaSO4: Vibrational modes and thermodynamics

Thermodynamic stability and correlation with synthesis conditions, structure and phase transformations in orthorhombic and monoclinic Li2M(SO4)2 (M = Mn, Fe, Co, Ni) polymorphs

“…Previous studies have revealed the feasibility of rotational disorder of SO 4 /ClO 4 À tetrahedra for many sulfates and perchlorates, frequently referred to as a "paddle wheel" mechanism of motion of the SO 4 /ClO 4 groups. [54][55][56][57][58][59][60][61] The TGA curves of both monoclinic and orthorhombic samples show a continuous weight loss below 250-300 C due to the presence of adsorbed water (see Table 1 for water contents). Despite all sample preparations being done in the glove box, the samples seem to have picked up adsorbed water, probably due to exposure to air (for 30-60 s) while loading them into the TGA/ IR instrument and/or dropping them into the calorimeter.…”

The Li2SO4–Na2SO4 System for Thermal Energy Storage

“…In particular, the composition corresponding to the stoichiometric compound LiNaSO 4 (lithium-sodium sulfate) is a well-known superionic conductor, which has a quasi-liquid cationic sub-lattice above 515 °C [13]. This material has been extensively studied both structurally, with the determination of the structural transformations by XRD analysis and in situ-XRD during heating [14], thermally with the determination of the enthalpy, the entropy the specific heat of the transformation, the thermal conductivity [15], the thermal expansion [16] and spectroscopically with different techniques such as NMR [17,18], Raman [19,20,21] and IR [22]. Moreover, deep studies relevant to the kinetics of the phase transition have been carried out enlightening the fast kinetics of the transformation characterized by a low energetic barrier for the transformation α ↔ β.…”

Lithium Nickel Cobalt Manganese Oxide Synthesized Using Alkali Chloride Flux: Morphology and Performance As a Cathode Material for Lithium Ion Batteries

“…Lithium nickel oxide (LiNiO 2 ; LNO) is a promising alternative to LiCoO 2 (LCO) which is widely used in lithium ion batteries. − LNO is isostructural with LCO, whose crystal structure consists of layers of transition metal cations separated from Li layers by oxygen and which belongs to the space group R3̅m. − LNO has a higher specific energy, is less toxic, and the raw materials are less expensive. − Because it is well-known that substitution of part of Ni with Co and/or Mn improves structural and thermal stability of the material, several composition of Li(Ni 1– x – y Co x Mn y )O 2 (NCM) have been developed and commercially available now. − NCM with 5:2:3 ratio of Ni, Co, and Mn (NCM523) is commercialized in particular, because it shows reasonable performances of capacity, stability, and safety.…”