The dissolution mechanism of polyacrylonitrile (PAN) in solvent (dimethyl sulfoxide (DMSO), N, N-dimethylacetamide (DMAC) or N, N-dimethylformamide (DMF)) was investigated by theoretical and experimental approach. Theoretical simulation revealed DMAc and DMF adopt planar two-dimensional structures with a resonance-stabilized N–C=O group, whereas DMSO exhibits a three-dimensional configuration. The dominant role of the interaction between free-state solvent molecules and PAN chains in the dissolution process was confirmed through analysis of zero-point energy between solvent–solvent and solvent–PAN. The interaction peaks assignment between solvent and PAN were identified by analyzing the Fourier transform infrared spectroscopy (FTIR) characteristic peaks of red or blue shift. By performing peak fitting on time- resolved attenuated total reflection FTIR spectroscopy revealed the mechanism of microscopic dissolution. Viscosity measurements showed an initial increase followed by a decrease and eventual stabilization of viscosity, demonstrating a swelling–dissolution mechanism.
Xu Su,Han Fang,Hao Yang,Fangfang Zou,Gang Li,Lian Wang,Hongxin Liao,Wei Guan,Xuebu Hu
Polysaccharides can be potential binders for lithium-ion batteries due to their strong adhesion through numerous hydroxyl groups . As a novel waterborne lithiated polysaccharide derivative, cellulose sulfate lithium (CSL) is successfully synthesized and used as the binder for LiFePO 4 (LFP) cathode. The chemical structure of CSL is verified by FTIR-ATR, XRD, C 13 -NMR, GPC , EA , ICP and TGA . Compared to LFP cathode using polyvinylidene difluoride binder, electrochemical measurements show that the LFP cathode using CSL (LFP-CSL) has lower polarization and better rate performance owing to higher lithium-ion conductivity of CSL. The result of morphological analysis indicates that CSL binder can maintain an integrated LFP cathode structure during hundreds of cycles. As a result, the LFP-CSL cathode exhibits a discharge capacity of 133.4 mAh g −1 and maintains remarkable cycle stability with retention of 93.1 % after 300 cycles at 1C. These findings provide novel insights into the rational design of the binders for the LFP cathode.
危险品化学品经营许可证（带存储）