Two novel ionic-liquid-based binary mixture systems of N,N-diethyl-N-(2-methoxyethyl)- N -methylammonium tetrafluoroborate ([DEME][BF 4 ]), or N,N-diethyl- N -methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([DEME][TFSI]) + γ-butyrolactone (GBL) are prepared over the whole concentration range (mole fraction from 0–1). Some important thermodynamic properties and parameters of the pure ILs and two systems were measured and calculated. The temperature dependences of the transport properties (viscosity and conductivity) were described by the Vogel–Fulcher–Tamman (VFT) equation. The excess molar volumes ( V E ) were obtained from the experimental densities and fitted to Redlich–Kister (R–K) polynomial equation. The DSC analysis, the shifts of the infrared (IR) spectrum, and COSMO–RS methodology based on DFT calculations were combined to explain the interaction information of GBL molecules and cations/anions of the selected systems. The stable optimized structures, interaction energies, and charge distributions were further obtained. Those maybe slight enlighten the application of similar mixture systems in future.
Bo Sun,Xiaona Pan,Yu Tian,Wenlong Bi,Menglin Feng,Fenwu Liu,Qingjie Hou
Microbial fuel cells (MFCs) represent a promising clean energy technology with significant application potential. However, their implementation is constrained by the limitations of current membrane materials. Polyvinylidene fluoride-hexafluoropropylene (PVDF-co-HFP) is a material that has garnered interest in the field of electrochemical systems because of its facile moldability into various shapes and sizes of membranes, positioning it as a highly promising alternative to high-cost commercial membranes. Nevertheless, enhancing its electrochemical characterization remains a pivotal challenge to be surmounted for its broad adoption. In this study, an efficient PVDF-co-HFP membrane, augmented with PP13-TFSI ionic liquid and sulfonation (Membrane P-I&S), was successfully synthesized, and its potential as an ion exchange membrane in MFCs was evaluated. The findings indicated that chlorosulfonic acid considerably enhances the hydrophilicity and proton transport properties of PVDF-co-HFP, with the ionic liquid posited as an effective means to augment the sulfonation effect. An MFCs incorporating Membrane P-I&S demonstrated a remarkable current production capacity and power density, exceeding those of the unmodified membrane by more than two and threefold, respectively. In addition, the MFCs based on Membrane P-I&S displayed prolonged cycling stability with a notably porous architecture and enhanced biofouling resistance. This study validates the development of a high-efficiency, cost-effective, and environmentally friendly membrane fabrication approach for application in bioelectrochemical systems. This will help promote the application of MFCs in the field of wastewater treatment and resource recovery.
Ying Wei,Wei Chen,Xinyi Ge,Jiayi Liang,Zheng Xing,Qingguo Zhang,Zhong-Xia Wang
Ionogel electrolytes (IGEs) with chemical and thermal stability properties have attracted considerable attention for all-solid-state energy storage devices, particularly for high-performance supercapacitors (SCs). However, achieving high conductivity, flexibility, and toughness, as well as deformation and impact resistance in special cases, is challenging with the typical polymer based on ionic liquids (ILs). Here, an effective gelation strategy is proposed for the preparation of free-standing LiTFSI/[EMIM][TFSI]/PVDF-HFP ionogels (IGs) by double-additive induced physical cross-linking. The mechanical and electrochemical properties of the IGs can be synergistically optimized by the cross-linking and entanglement of LiTFSI and [EMIM][TFSI] with the PVDF-HFP network. The target IGs simultaneously exhibit excellent deformation capacity (over 50 %), high ionic conductivity (10.3 × 10 −3 S cm −1 at 25 °C), hardness (H: 728.6 kPa), and Young's modulus (E: 11.4 MPa), which can exhibit the specific capacitance of 274. 55 F g −1 , energy density of 38.13 Wh kg −1 and maximum power density of 2499.93 W kg −1 in the fabricated symmetric supercapacitor . The results will motivate us to further explore their applications for flexible electronic devices, wearable electronic skin, and flexible energy storage.