THE EFFECTS OF OVEROXIDATION ON THE MORPHOLOGICAL AND ELECTRICAL PROPERTIES OF POLYANILINE (PANI)  BASED SOLID POLYMER ELECTROLYTE (SPE)

Nur Najiha Maliaman; Saiful ‘Arifin  Shafiee; Muhammad Zharfan Mohd Halizan; Awatif  Hassim; Siti Nur Amira Shaffee; Muhammad Faiz Aizamddin; Mohamad Arif Kasri; Mohd Muzamir  Mahat

Nur Najiha Maliaman UITM SHAH ALAM
Saiful ‘Arifin Shafiee Department of Chemistry, Kuliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, 25200 Kuantan, Pahang, Malaysia https://orcid.org/0000-0003-0907-624X
Muhammad Zharfan Mohd Halizan Faculty of Applied Science, Universiti Teknologi MARA, 02600 Arau, Perlis, Malaysia https://orcid.org/0000-0003-4436-7800
Awatif Hassim Faculty of Applied Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
Siti Nur Amira Shaffee Group Research and Technology, PETRONAS Research Sdn. Bhd., Bandar Baru Bangi 43000 Selangor, Malaysia.
Muhammad Faiz Aizamddin Group Research and Technology, PETRONAS Research Sdn. Bhd., Bandar Baru Bangi 43000 Selangor, Malaysia.
Mohamad Arif Kasri Department of Chemistry, Kuliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, 25200 Kuantan, Pahang, Malaysia
Mohd Muzamir Mahat Faculty of Applied Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia https://orcid.org/0000-0002-2448-3241

Keywords: Polyaniline, overoxidation, interpenetrating network, conducting polymer, solid polymer electrolyte

Abstract

Overoxidation in lithium-ion batteries (LIBs) can occur when a solid polymer electrolyte (SPE) undergoes extreme oxidation, forming undesirable functional groups like carbonyl and hydroxyl. This work examines the effects of overoxidation on polyaniline (PANI)-based SPEs, focusing on morphological, electrical, and structural changes. SPE films composed of PANI, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were prepared with varying PANI concentrations (1 wt.%, 3 wt.%, and 5 wt.%) and subjected to overoxidation via cyclic voltammetry (CV). Fourier-transform infrared spectroscopy (FTIR) was used to characterize the structural changes, while electrochemical impedance spectroscopy (EIS) assessed electrical conductivity. The highest initial conductivity (1.8×10^-5 S/cm) was observed in the composite with 1 wt.% PANI, decreasing to 1.79×10^-6 S/cm after overoxidation. Composites with 3 wt.% and 5 wt.%. PANI exhibited lower initial conductivities of 1.41×10^-6 S/cm and 1.25×10^-6 S/cm, respectively, which further dropped to 4.17×10^-7 S/cm and 1.79×10^-7 S/cm post-overoxidation. Field-emission scanning electron microscopy (FESEM) revealed that the interpenetrating polymer network (IPN) structures present before treatment were disrupted after overoxidation. FTIR confirmed the formation of hydroxyl and carbonyl species, which correlate with reduced conductivity and degradation of the SPE material. These findings illustrate the detrimental effects of overoxidation on PANI-based SPEs, impacting their structural integrity, morphology, and electrical performance. This has significant implications for LIB efficiency and highlights the importance of mitigating overoxidation in SPEs.