TY - JOUR

T1 - Effect of Cation Size and Symmetry in Substituted Ammonium Tetrafluoroborates on Their Thermal, Structural, and Transport Properties

AU - Stebnitskii, Ivan

AU - Mateyshina, Yulia

AU - Chuikov, Igor

AU - Uvarov, Nikolai

N1 - Effect of Cation Size and Symmetry in Substituted Ammonium Tetrafluoroborates on Their Thermal, Structural, and Transport Properties / I. Stebnitski, Y. Mateyshina, I. Chuikov, N. Uvarov // The Journal of Physical Chemistry C. - 2025. - Т. 129. № 36. - С. 16380-16387. DOI: 10.1021/acs.jpcc.5c04256

PY - 2025

Y1 - 2025

N2 - In recent years, organic ionic plastic crystals (OIPCs) have been considered as a promising class of solid electrolytes due to their exceptional thermal and electrochemical stability, as well as their plasticity. However, the relationship between their chemical structures and physicochemical properties remains poorly understood. This study investigates how thermal properties and ionic conductivity correlate with cation size and symmetry in two series of substituted ammonium tetrafluoroborates: (CnH2n+1)4NBF4 (n = 1–6) and (C4H9)4–y(CH3)yNBF4 (y = 0–2). Combined thermal and X-ray diffraction analyses reveal that low-symmetry cations with extended alkyl chains (e.g., (C4H9)2(CH3)2NBF4) exhibit the widest plastic phase range (19–128 °C) and highest ionic conductivity (3.5 × 10–7 S/cm at 100 °C). In contrast, symmetrical cations show size-dependent conductivity, peaking at 4.0 × 10–8 S/cm at 100 °C for (C4H9)4NBF4. Both candidates demonstrate electrochemical stability windows of 4.7–5.2 V. These findings establish clear design principles for optimizing OIPCs, enabling the targeted synthesis of materials with enhanced physicochemical properties.

AB - In recent years, organic ionic plastic crystals (OIPCs) have been considered as a promising class of solid electrolytes due to their exceptional thermal and electrochemical stability, as well as their plasticity. However, the relationship between their chemical structures and physicochemical properties remains poorly understood. This study investigates how thermal properties and ionic conductivity correlate with cation size and symmetry in two series of substituted ammonium tetrafluoroborates: (CnH2n+1)4NBF4 (n = 1–6) and (C4H9)4–y(CH3)yNBF4 (y = 0–2). Combined thermal and X-ray diffraction analyses reveal that low-symmetry cations with extended alkyl chains (e.g., (C4H9)2(CH3)2NBF4) exhibit the widest plastic phase range (19–128 °C) and highest ionic conductivity (3.5 × 10–7 S/cm at 100 °C). In contrast, symmetrical cations show size-dependent conductivity, peaking at 4.0 × 10–8 S/cm at 100 °C for (C4H9)4NBF4. Both candidates demonstrate electrochemical stability windows of 4.7–5.2 V. These findings establish clear design principles for optimizing OIPCs, enabling the targeted synthesis of materials with enhanced physicochemical properties.

UR - https://www.mendeley.com/catalogue/6441951f-3596-36bd-90c9-b1530e611aaa/

U2 - 10.1021/acs.jpcc.5c04256

DO - 10.1021/acs.jpcc.5c04256

M3 - Article

VL - 129

SP - 16380

EP - 16387

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 36

ER -