TY - JOUR

T1 - «Structure–property» correlations and rational design of organic ionic plastic crystals

AU - Stebnitskii, Ivan

AU - Mateyshina, Yulia

AU - Uvarov, Nikolai

N1 - Stebnitskii I., Mateyshina Y., Uvarov N. «Structure–property» correlations and rational design of organic ionic plastic crystals. Chimica Techno Acta, 2025, vol. 12(4), 917. DOI: 10.15826/chimtech.9172 This work was supported by the Russian Science Foundation (grant no. 25-23-00263, https://www.rscf.ru/en).

PY - 2025/11/21

Y1 - 2025/11/21

N2 - Organic ionic plastic crystals (OIPCs) are promising solid electrolyte materials due to their high ionic conductivity, intrinsic plasticity, and thermal stability. However, the absence of universal structure-property relationships has hindered their targeted design. This work analyzes the thermal, crystallochemical, and transport properties of 49 OIPCs from diverse structural families, including tetraalkylammonium, tetraalkylphosphonium, pyrrolidinium, oxazolidinium, and guanidinium salts. Strong correlations (rPearson up to –0.79) were identified between ionic conductivity and key parameters: the enthalpy ( ) and entropy ( ) of melting, and the anion-to-cation volume ratio. The highest conductivities are achieved in compounds with low and an optimal volume ratio of ~0.2–0.3. Empirical equations for predicting conductivity were developed based on these correlations. The predictive power of this model was experimentally validated by synthesizing and characterizing a novel OIPC, N-methyl-N-ethylmorpholinium tetrafluoroborate ([C₂mmor][BF₄]). Its experimental conductivity (log(σ, S∙cm−1) = −4.15 at 100 °C) aligns closely with predictions. These findings provide a robust framework for the accelerated discovery of high-performance OIPCs for advanced electrochemical devices.

AB - Organic ionic plastic crystals (OIPCs) are promising solid electrolyte materials due to their high ionic conductivity, intrinsic plasticity, and thermal stability. However, the absence of universal structure-property relationships has hindered their targeted design. This work analyzes the thermal, crystallochemical, and transport properties of 49 OIPCs from diverse structural families, including tetraalkylammonium, tetraalkylphosphonium, pyrrolidinium, oxazolidinium, and guanidinium salts. Strong correlations (rPearson up to –0.79) were identified between ionic conductivity and key parameters: the enthalpy ( ) and entropy ( ) of melting, and the anion-to-cation volume ratio. The highest conductivities are achieved in compounds with low and an optimal volume ratio of ~0.2–0.3. Empirical equations for predicting conductivity were developed based on these correlations. The predictive power of this model was experimentally validated by synthesizing and characterizing a novel OIPC, N-methyl-N-ethylmorpholinium tetrafluoroborate ([C₂mmor][BF₄]). Its experimental conductivity (log(σ, S∙cm−1) = −4.15 at 100 °C) aligns closely with predictions. These findings provide a robust framework for the accelerated discovery of high-performance OIPCs for advanced electrochemical devices.

KW - organic ionic plastic crystals

KW - melting temperature, enthalpy and entropy

KW - ionic conductivity

KW - pearson coefficient

KW - prediction of properties

KW - structure–property correlations

KW - rational design

KW - ion volume ratio

UR - https://www.scopus.com/pages/publications/105026272487

U2 - 10.15826/chimtech.9172

DO - 10.15826/chimtech.9172

M3 - Article

VL - 12

JO - Chimica Techno Acta

JF - Chimica Techno Acta

SN - 2409-5613

IS - 4

M1 - 9172

ER -