Unravelling the alkali transport properties in nanocrystalline A₃OX (A = Li, Na, X = Cl, Br) solid state electrolytes. A theoretical prediction

Abstract

Transport properties of the halogeno-alkali oxides A3OX (A = Li, Na, X = Cl, Br) nanocrystalline samples with the presence of ∑3(111) grain boundaries were computed using large-scale molecular dynamic simulations.

Determination of the ion-conduction properties of Na3OBr and its dominant defect species

“…Duong et al have reported a deterioration in the ion-transport properties of nanocrystalline APs due to the (111) grain boundary. 36 Here, the crystallite size was ∼23 nm; therefore, the grain-boundary contribution should not be ignored for the hot-pressed pellets (Fig. S6 in the ESI †).…”

Theoretical approaches to defect mechanisms and transport properties of compounds used for electrodes and solid-state electrolytes in alkali-ion batteries

“…For a successful use as an electrode and electrolyte in an alkali-ion battery, the material should satisfy specific requirements, some of those key requirements are common for both the electrode and the electrolyte. [1][2][3][4][5][6][7][8][9][10][11][12][13] The principal prerequisites for a material to be considered as a main component of a rechargeable alkali-ion battery are: the material (a) contains a reducible/oxidisable ion, such as a transition metal atom (for the positive electrode being called the cathode), (b) has high chemical and mechanical stability, reacting reversibly with the alkali-ion with a minimal structural change upon insertion/extraction of the alkali-ion leading to good cycle life, (c) has excellent electronic and alkali-ion conductivity facilitating the electrochemical reaction, (d) accommodates several alkali-ions per metallic alkali in order to provide high capacity and energy density, (e) having a high voltage for the cathode (E4 V) and a low voltage for the anode (E0.5 V) to satisfy the 5 V electrochemical window for the electrolyte stability, and (f) low cost and environmentally benign. In addition, the solid-state electrolyte must be malleable (having a reasonably small Young's Modulus and being mechanically stable), ensuring good contact with the electrodes, and possessing insulating electronic characteristics to avoid reactions with the electrodes which cause undesirable alkali loss during the charge/discharge process, dendrite formation and high electronic conductivity through the electrolyte (producing possible short-circuit).…”

“…In addition, the solid-state electrolyte must be malleable (having a reasonably small Young's Modulus and being mechanically stable), ensuring good contact with the electrodes, and possessing insulating electronic characteristics to avoid reactions with the electrodes which cause undesirable alkali loss during the charge/discharge process, dendrite formation and high electronic conductivity through the electrolyte (producing possible short-circuit). [1][2][3][4][5][6][7][8][9][10][11][12][13] Throughout this paper, a material with a potential application as an electrode (either a cathode or an anode) and an electrolyte, as well as a coating electrode, is labelled a battery material.…”

“…Therefore, advanced atomistic simulations can help the experimentalists to select appropriate dopants to improve a particular property, alleviating negative effects. [1][2][3][4][5][6][7][8][9][10]22,23 This manuscript is devoted to a review of our recent advances in the design of selected battery materials. The structural and electronic properties, thermodynamic stability, defect chemistry and transport properties of a series of compounds, including Li 2 SnO 3 , Li 2 SiO 3 , SrSnO 3, A 2 B 6 X 13 (A = Li + , Na + , or K + ; B = Ti 4+ or Sn 4+ ; X = O 2À or S 2À ) and alkali-halide oxides A 3 OX (A = Li, Na, X = Cl or Br), are explored employing advanced atomistic simulations.…”

Theoretical Prediction of Spinel Na2InxSc0.666−xCl4 and Rock‐Salt Na3In1−xScxCl6 Superionic Conductors for All‐Solid‐State Sodium‐Ion Batteries

“…Oxidebased sodium solid electrolytes have been developed as another typical series of electrolytes for ASSSIBs, for example, 𝛽-Al 2 O 3 , Na 3.4 Sc 0.4 Zr 1.6 (SiO 4 ) 2 (PO 4 ), NASICON NaZr 2 (PO 4 ) 3 , and anti-perovskite (Na 3 OCl and Na 3 OBr). [18][19][20][21][22][23][24][25][26] They have displayed higher air stabilities and better electrode compatibilities than the sulfide electrolytes, but their ionic conductivities are slightly lower and their intrinsic brittleness will add more challenges for cell manufacturing. Other inorganic materials, such as complex hydrides, [27] have also been studied but received much less attention than the sulfide-and oxide-based electrolytes due to the unsatisfying ionic conductivity.…”