Rafizah Rahamathullah
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Preferred name
Rafizah Rahamathullah
Official Name
Rafizah, Rahamathullah
Alternative Name
Rahamathulla, Rafizah
Rahamathullah, R.
Main Affiliation
Scopus Author ID
55764144700
Researcher ID
DMZ-6313-2022

Research Output
Now showing 1 - 2 of 2
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Publication

The effect of NHâ‚„Br composition on electrical behaviour of 2-Hydroxyethyl cellulose solid biopolymer electrolytes

2025-02 , Nurul Faeqah Mazalan , Mohd Ibnu Haikal Ahmad Sohaimy , Azwani Sofia Ahmad Khiar , Wan Mohd Khairul Wan Mohamed Zin , Md Uwaisulqarni Osman , Mohammad Fakhratul Ridwan Zulkifli , Rafizah Rahamathullah , Muthiah Muthuvinayagam , Mohd Ikmar Nizam Mohamad Isa

In this study, solid biopolymer electrolytes (SBEs) were developed as an alternative to liquid electrolytes for battery applications. 2-hydroxyethyl cellulose (2HEC) served as the polymer host in the preparation of SBE films, incorporating varying amounts of ammonium bromide (NH4Br). The films were then analysed using electrical impedance spectroscopy (EIS) to investigate its electrical properties. The system containing 20 wt.% of NH₄Br achieved the highest conductivity at 3.9510-5 Scm-1 at ambient temperature of 303 K. The 2HEC-NH₄Br SBE film system was subjected to temperature variations between 303 K – 373 K in increments of 10 °C, revealing an increase in conductivity with rising temperature. This observation suggests that the SBE system adheres to the Arrhenius law, enabling the determination of the activation energy (Ea) through temperature dependence plotting. The Ea for the most conductive system reflects the lowest energy, indicating minimal energy required for the excitation process within the polymer chain. This Ea value offers a deeper insight into the transport parameters, including the number of mobile ions, ions mobility and diffusion coefficient, as determined through the Rice and Roth method.

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Publication

The influence of Ammonium Formate concentration on the electrical performance of 2-Hydroxyethyl cellulose solid biopolymer electrolytes

2025 , Nur Maisarah Batrisyia Mohd Bahaudin , Mohd Ibnu Haikal Ahmad Sohaimy , Syahida Suhaimi , Wan Mohd Khairul Wan Mohamed Zin , Md Uwaisulqarni Osman , Mohamad Fakhratul Ridwan Zulkifli , Rafizah Rahamathullah , Muthuvinayagam Muthiah , Mohd Ikmar Nizam Mohamad Isa

Novel solid biopolymer electrolytes (SBE) with various amounts of ammonium formate (AF) salt doped into 2-hydroxyethyl cellulose (2-HEC) are fabricated by using a well-known technique, solution casting. The SBEs are developed mainly to address the leakage, toxic material issues, safety concerns, and costs associated with conventional liquid-based electrolytes. The 2-HEC-based SBE is analyzed for its ionic conductivity and electrical properties. The highest ionic conductivity achieved was 2.40 × 10-3 S/cm for AF40 (40 wt.% AF salt). The bulk resistance value obtained at ambient and elevated temperatures emphasizes its effect on ionic conductivity and electrical behavior regarding its dielectric permittivity. The activation energy from the temperature-dependent ionic conductivity indicates that activation energy decreases with increasing temperature. The two primary transport parameters affecting the system's ionic conductivity based on the Rice and Roth model are the diffusion coefficient (D) and ion mobility (µ). This study showed that the rise in ionic conductivity depends on the concentration of ammonium formate salt.

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