High Performance of Transferring Lithium Ion for Polyacrylonitrile-Interpenetrating Crosslinked Polyoxyethylene Network as Gel Polymer Electrolyte

Abstract

A polyacrylonitrile (PAN)-interpenetrating cross-linked polyoxyethylene (PEO) network (named XANE) was synthesized acting as separator and as gel polymer electrolytes simultaneously. SEM images show that the surface of the XANE membrane is nonporous, comparing to the surface of the commercial separator to be porous. This property results in excellent electrolyte uptake amount (425 wt %), and electrolyte retention for XANE membrane, significantly higher than that of commercial separator (200 wt %). The DSC result indicates that the PEO crystallinity is deteriorated by the cross-linked process and was further degraded by the interpenetration of the PAN. The XANE membrane shows significantly higher ionic conductivity (1.06-8.21 mS cm(-1)) than that of the commercial Celgard M824 separator (0.45-0.90 mS cm(-1)) ascribed to the high electrolyte retention ability of XANE (from TGA), the deteriorated PEO crystallinity (from DSC) and the good compatibility between XANE and electrode (from measuring the interfacial-resistance). For battery application, under all charge/discharge rates (from 0.1 to 3 C), the specific half-cell capacities of the cell composed of the XANE membrane are all higher than those of the aforementioned commercial separator. More specifically, the cell composed of the XANE membrane has excellent cycling stability, that is, the half-cell composed of the XANE membrane still exhibited more than 97% columbic efficiency after 100 cycles at 1 C. The above-mentioned advantageous properties and performances of the XANE membrane allow it to act as both an ionic conductor as well as a separator, so as to work as separator-free gel polymer electrolytes.

Effect of polyacrylonitrile on triethylene glycol diacetate-2-propenoic acid butyl ester gel polymer electrolytes with interpenetrating crosslinked network for flexible lithium ion batteries

“…The more favorable discharge capacity retention after high rate cycling can be ascribed to the improved interpenetrating crosslinked network, stable electrolyte/electrode interface and low depletion of the irreversible Li ions [12]. The interpenetrating crosslinked network is beneficial for providing excellent ionic channel, which mitigates the ohmic polarization and reduces irreversible Li ion loss during charge/discharge [28].…”

“…The blending TEGDA-BA/PAN polymer network possesses more compact rumple than that of TEGDA-BA, which significantly contributes to the improved mechanical toughness. The unique morphology of the electrolytes is expected to play a key role in providing significant improvements in the interface stability and cycle stability [28]. The self-supported GPE has excellent flexibility through blending PAN polymer matrix and TEGDA-BA framework, which exhibits great enhancement in the mechanical integrity.…”

“…The detailed reactive process and chemical intermediates can be observed and identified by using electron paramagnetic resonance spectroscopy [58]. Besides, the reaction between the lithium metal and carbonate organic solvent is inhibited by the interpenetrating crosslinked network, and the growth rate of the passivation layer is reduced [28]. Fig.…”

“…Various polymer matrices, such as polyethylene oxide (PEO) [11,12], polyacrylonitrile (PAN) [13,14], polyvinylidene fluoride (PVDF) [15e17], poly(vinylidene fluoridehexafluoro propylene) (PVDF-HFP) [18,19], polymethylmethacrylate (PMMA) [20,21], polyimide (PI) [22,23], poly(urethane) (PU) [24,25] and etc., have been widely developed as candidate materials for the preparation of polymer electrolytes. Especially, PAN have been developed and attracted as the main component for applications not only in electric double layer capacitors [26,27], but also in LIBs [28,29]. GPE can be prepared by solvent-casting techniques [30,31], thermally induced phase separation [32,33], electrospinning technology [34,35] and in situ polymerization [36,37].…”

“…Significant efforts have been made to enhance physical and electrochemical performance, such as grafting [44], blending [45], copolymerizing [46] and incorporating inorganic fillers [47,48] into polymer matrices. In comparison, interpenetrating crosslinked networks by blending different polymeric matrices are capable of providing enhanced mechanical flexibility and compatibility for the electrodes, which is essential for improving safety operation in the charge/discharge cycling processes [28,49].…”