Experimental and Theoretical Study of Ionic Pair Dissociation in a Lithium Ion–Linear Polyethylenimine–Polyacrylonitrile Blend for Solid Polymer Electrolytes

Abstract

Herein, we report the preparation and characterization of a novel polymeric blend between linear polyethylene imine (PEI) and polyacrylonitrile (PAN), with the purpose of facilitating the dissociation of lithium perchlorate salt (LiClO) and thus to enhance Li ion transport. It is a joint theoretical and experimental procedure for evaluating and thus demonstrating the lithium salt dissociation. The procedure implies the correlation between the theoretical pair distribution function (PDF) and conventional X-ray diffraction (XRD) by means of a molecular dynamics (MD) approach. Additionally, we correlated the experimental and theoretical Raman and infrared spectroscopy for vibrational characterization of the lithium salt after dissociation in the polymeric blend. We also performed confocal Raman microscopy analysis to evidence the homogeneity on the distribution of all components and the LiClO dissociation in the polymer blend. The electrochemical impedance analysis confirmed that the Li-PAN-PEI blend presents a slightly better lithium conductivity of ∼8 × 10 S cm. These results suggest that this polymer blend material is promising for the development of novel fluorine-free solid polymer lithium ion electrolytes, and the methodology is suitable for characterizing similar polymeric systems.

Polyacrylonitrile–poly(1‐vinyl pyrrolidone‐co‐vinyl acetate) blend based gel polymer electrolytes incorporated with sodium iodide salt for dye‐sensitized solar cell applications

“…It also showed a broad peak at a 2θ of 28 , which described the amorphous region. 40,50 We also observed that there were several diffractions in the XRD spectrum of NaI; these indicated the highly crystalline nature of the salt. 51 The diffraction peak of the sample without salt, N0, showed the overlap of the peak due to interactions between these two polymers and the copolymer as well as the NaI salt by blending.…”

“…From the XRD pattern of the PAN polymer, we observed that the characteristic peak at 17° indicated the semicrystalline nature and corresponded to the orthorhombic PAN (110) reflection. It also showed a broad peak at a 2θ of 28°, which described the amorphous region . We also observed that there were several diffractions in the XRD spectrum of NaI; these indicated the highly crystalline nature of the salt .…”

Hybrid Organic-Inorganic Materials and Interfaces With Mixed Ionic-Electronic Transport Properties: Advances in Experimental and Theoretical Approaches

“…graphene, thiophene oligomers) ( Ling and Zhang, 2010 ; Yu et al, 2011 ; Ling et al, 2012 ; Ling et al, 2013 ; Huang et al, 2015 ; Kang et al, 2015 ; Zhang et al, 2016b ; Lombardi, 2017 ; Yilmaz et al, 2017 ; Liu et al, 2018 ) semiconductors is rising and appears to be a very promising technique to study h OI interfaces. Not only there is a vast experimental database that can be useful for vibrational modes assignment but also infrared and, to a lesser extent, Raman spectra can be easily computed using first-principles calculations ( Mombrú et al, 2017a ; Wang et al, 2020a ; Schöttner et al, 2020 ; Fernández-Werner et al, 2017 ; Pignanelli et al, 2017 ). Undoubtedly, nuclear magnetic resonance and X-ray photoelectron spectroscopies are other powerful tools to obtain chemical information about h OI interfaces but are less accessible than vibrational spectroscopies and computational calculations demand a high computational cost.…”

“…High-resolution electron, atomic force and tunneling microscopies can give direct local information about h OI materials and interfaces but it is almost impossible to access a large amount of sample as in the case of using X-ray scattering techniques, thus both techniques should be complemented. Furthermore, the modeling of X-ray scattering data by using Rietveld (for crystalline) or Debye (for both crystalline and amorphous) methodologies are quite simple to perform and can be also assisted by classical molecular dynamics calculations ( Scardi and Gelisio, 2016 ; Fernández-Werner et al, 2017 ; Pignanelli et al, 2017 ; Bokuniaeva and Vorokh, 2019 ; Bertolotti et al, 2020 ).…”

“…To have direct insight on ionic transport for h OI materials and interfaces, larger-scale approaches using non-atomistic or atomistic calculations including organic oligomers and inorganic clusters or surfaces are necessary. MD can provide rich information about ion diffusion and transport directly from the trajectories but these calculations need to be conducted over sufficiently long time scales ( Webb et al, 2015 ; Deng et al, 2016 ; Sun et al, 2016 ; Mogurampelly et al, 2017 ; Pignanelli et al, 2017 ; Xue et al, 2017 ; Patra et al, 2019 ; Pignanelli et al, 2021 ). However, such long-time scales are highly demanding for AIMD and this first-principle approach is rare in large systems (such as amorphous solids) and it is more usually performed for relatively small crystalline systems ( Jalem et al, 2013 ; Meier et al, 2014 ; Mo et al, 2014 ).…”