Ahmad Azmin Mohamad

Ionic conductivity studies of poly(vinyl alcohol) alkaline solid polymer electrolyte and its use in nickel–zinc cells

Abstract X-ray diffraction (XRD) pattern reveals that potassium hydroxide (KOH) disrupts the crystalline nature of poly(vinyl alcohol) (PVA)-based polymer electrolytes and converts them into an amorphous phase. The PVA–KOH alkaline solid polymer electrolyte (ASPE) system with PVA/KOH wt.% ratio of 60:40 exhibits the highest room temperature ionic conductivity of 8.5×10−4 S cm−1. This electrolyte was used in the fabrication of a nickel–zinc (Ni–Zn) cell. The cell was charged at a constant current of 10 mA for 1 h providing it with 1.6 V. The cell was cycled 100 times. At the end of the last cycle, the cell still contained a capacity of 5.5 mA h.

Studies of alkaline solid polymer electrolyte and mechanically alloyed polycrystalline Mg2Ni for use in nickel metal hydride batteries

Ni–MH cells comprising PVA-KOH solid polymer electrolyte and mechanically alloyed Mg2Ni as the negative electrode have been fabricated. The alkaline solid polymer electrolyte with PVA:KOH wt.% ratio of 60:40 exhibits the highest room temperature ionic conductivity of 8.5×10−4 S cm−1. This sample is mostly amorphous. The cell was charged at a constant current of 10 mA and discharged at 0.1 mA. The discharge characteristics improved upon cycling and the plateau voltage maintained above 1.2 V for ∼10 h.

Electrical conductivity studies on PVA/PVP-KOH alkaline solid polymer blend electrolyte

A series of conducting thin-film solid electrolytes based on poly (vinyl alcohol)/ poly (vinyl pyrrolidone) (PVA/PVP) polymer blend was prepared by the solution casting technique. PVA and PVP were mixed in various weight percent ratios and dissolved in 20 ml of distilled water. The samples were analyzed by using impedance spectroscopy in the frequency range between 100 Hz and 1 MHz. The PVA/PVP system with a composition of 80% PVA and 20 wt.% PVP exhibits the highest conductivity of (2.2±1.4) × 10−7 Scm−1. The highest conducting PVA/PVP blend was then further studied by adding different amounts of potassium hydroxide (KOH) ionic dopant. Water has been used as solvent to prepare PVA/PVP-KOH based alkaline solid polymer blend electrolyte films. The conductivity was enhanced to (1.5 ± 1.1) × 10−4 Scm−1 when 40 wt.% KOH was added.

Interfacial Reaction of Sn-Ag-Cu Lead-Free Solder Alloy on Cu: A Review

This paper reviews the function and importance of Sn-Ag-Cu solder alloys in electronics industry and the interfacial reaction of Sn-Ag-Cu/Cu solder joint at various solder forms and solder reflow conditions. The Sn-Ag-Cu solder alloys are examined in bulk and in thin film. It then examines the effect of soldering conditions to the formation of intermetallic compounds such as Cu substrate selection, structural phases, morphology evolution, the growth kinetics, temperature and time is also discussed. Sn-Ag-Cu lead-free solder alloys are the most promising candidate for the replacement of Sn-Pb solders in modern microelectronic technology. Sn-Ag-Cu solders could possibly be considered and adapted in miniaturization technologies. Therefore, this paper should be of great interest to a large selection of electronics interconnect materials, reliability, processes, and assembly community.

Synthesis of Zinc Oxide by Sol–Gel Method for Photoelectrochemical Cells

This chapter discussed the fundamentals, properties and applications. The ZnO properties will mainly focus on structural, electronic and optical. Finally, this chapter discussed the synthesis sol–gel method.

Electrical Properties of Plasticized Chitosan-Lithium Imide with Oleic Acid- Based Polymer Electrolytes for Lithium Rechargeable Batteries

Solid polymer electrolytes (SPEs) were prepared and their electrochemical characteristics were characterized. The composition of SPEs containing chitosan, lithium trifluoromethane sulfonimide (LiN(CF3SO2)2) and oleic acid (OA) was optimized employing ac impedance measurements at various temperatures. The electrical conductivity of the SPEs with OA shows the highest value and the presence of OA does not change the structure of the polymer.

Interfacial reaction of a Sn‐3.0Ag‐0.5Cu thin film during solder reflow

Purpose – The purpose of this paper is to produce and investigate the interfacial reaction between Sn‐3.0Ag‐0.5Cu (SAC305) thin films and Cu substrates by solder reflow at various temperatures and times.Design/methodology/approach – SAC305 thin films were deposited on copper substrates using a thermal evaporation technique. The as‐deposited SAC305/Cu was then reflowed on a hot plate at temperatures of 230, 240, 250 and 260°C for 30 s. In addition, solder reflow was conducted at a constant temperature of 230°C for 5, 10, 15 and 20 s. The microstructure, phase and thickness of the intermetallic compounds (IMCs) formed were determined after cross‐sectional metallographic preparation.Findings – Cu6Sn5 and Cu3Sn were observed at the as‐reflowed SAC305/Cu interfacial region. The IMC thicknesses increased with the higher reflow temperature and longer reflow times.Originality/value – Up to now, studies on the thin film characteristics of SAC305 lead‐free solder have been very limited. Thus, this paper presents th...

Proton batteries with hydroponics Gel as Gel polymer electrolyte

A proton conductor gel polymer electrolyte based on hydroponics gels (HPG) mixed with 10 M ammonium nitrate (NH 4 NO 3 ) was found to yield a very high electrical conductivity of 0.60 S cm -1 . The optimized composition, i.e., the HPG-10 M NH 4 NO 3 , was then used in our proton battery to make a Zn + ZnSO 4 ·7H 2 O/HPG-10 M NH 4 NO 3 /MnO 2 system. The open-circuit voltage of the battery was 1.42 V during 24 h of storage. The battery obtained a capacity of 14.67 mAh and a maximum specific energy of 18.96 mW cm -2 .

Sago Gel Polymer Electrolyte for Zinc-Air Battery

A sago-based gel polymer electrolyte (GPE) was prepared by mixing native sago with potassium hydroxide (KOH) aqueous in order to investigate the applicability of GPE to zinc-air (Zn-air) battery. The viscosity and conductivity of the sago GPE were evaluated using varying sago amounts and KOH concentrations. The viscosity of the sago GPE was kept as a reserve in the region of ~ 0.2 Pa s as the KOH concentration was increased from 2 to 8 M. Sago GPE was found to have an excellent ionic conductivity of (4.45  0.1) x 10-1 S cm-1 with 6 M KOH. GPE was also employed in an experimental Znair battery using porous Zn electrode as the anode. The battery shows outstanding discharge capacity and practical capacity obtained of 505 mA h g-1.

ZnO Nanocrystalline Metal Oxide Semiconductor Via Sol Gel Method

This chapter discussed the fundamentals, properties and applications. The ZnO properties will mainly focus on structural, electronic and optical. Finally, this chapter discussed the synthesis sol–gel method.