Strontium Stannate as an Alternative Anode Material for Li-Ion Batteries

Abstract

Although strontium stannate (SrSnO 3 ) has been considered as an anode for Li-ion batteries, a deep understanding of its Li-ion transport properties remains lacking. In this work, the structural, electronic, mechanical, and transport properties of SrSnO 3 are explored using density functional theory and force-field-based simulations. Our results show that the norm-conserving approximation is particularly accurate for reproducing the lattice parameters and electronic structure of SrSnO 3 . SrSnO 3 exhibits an indirect energy gap of ∼3.0 eV, in agreement with the experiment. SrSnO 3 is a mechanically stable and a quasi-brittle material that is also more isotropic with respect to the volume change than the shape change. Defect energy simulations reveal a low energetic cost for the Li-ion incorporation mechanism proposed, which is beneficial for its potential application as an electrode material. A comparison of the Li-ion transport properties of Li-doped mono-and nanocrystalline SrSnO 3 samples reveals that the nanocrystalline material exhibits a lower diffusion activation energy of ∼0.28 eV and higher diffusivity at operative temperature. The understanding and properties illustrated in this work open an avenue for the consideration of SrSnO 3 as a potential candidate to be used as an anode for Li-ion batteries.

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

“…Defect energetics computations were performed in considering the incorporation mechanism involving A + interstitial and Sr-vacancy as predominant point defects. 8,9 Fig. 4 The results of defect energetics computations point out that the SSO structure accepts the inclusion of A + interstitially with a low energetic cost.…”

“…15,[22][23][24] We have used various computational methods to investigate the structural and electronic properties, mechanical and thermodynamic stability, defect formation and migration in relevant battery materials. [1][2][3][4][5][6][7][8][9][10] These methods are summarized in the ESI † for disseminating these computational protocols and stimulating their use by the readers.…”

“…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.…”