No abstract

LiFePO4 (LFP) cathode material has been synthesized with hydrothermal method. The reaction was done by reacting a mixture of FeSO4.7H2O, H3PO4, LiOH and CNT. In order to improve performance of LFP, the carbon nano tube (CNT) was added with the variation of 5, 10 and 15 mmol, before hydrothermal process. The material was stirred using a magnetic stirrer for 30 minutes, and then autoclave was heated at 180°C for 6 hours then sintered at 700°C for 6 hours. The results were characterized by X-ray diffraction (XRD), and Scanning Electron Microscope (SEM), and Impedance Spectroscopy (EIS). The X-ray data shows that the crystal structure of synthesized LiFePO4 has a group of Pmn with a space (olivine structure) which is in agreement with the LFP standard material. The addition of CNT does not change the crystal structure. This shows in SEM images that the crystallite size of LiFePO4 particles does not have much effect on the composite. The battery cell performance was measured by Impedance Spectroscopy and charge/discharge Battery Analyzer BST-8. The EIS data, showed the decreasing of battery impedance total from LiFePO4 material without CNT to addition of 5, 10 and 15 mmol CNT namely 214; 128.1; 88.6 and 70.1 Ω, and the specific capacity 0.1C are 38.78; 51.53; 106.84; 92.79 mAh/g, respectively. It is shown that the maximum specific capacity was obtained for LFP composite with the addition of 10mmol CNT. It can be concluded that the addition of CNT increases the conductivity and specific capacity, thus improving performance of lithium ion battery.

A module of lithium ion battery has been constructed to replace ion battery for public street lighting. The module was designed to deliver a power of minimum~120 Wh for running 10 Watt solar street llighting, with a solar panel of 80 Wp. The module consisted of 40 cylinder cells 18650 of LiFePO4. Before designing the module, all the cells have to be formatted, graded and sorted out, to obtain an optimum results. The charge-discharge testing and internal resistance were measured to every single cell using a battery analyzer. The cells grading,sorting and grouping were consecutively done to obtain an optimum LIB module. The results showed each cylinder cell delivering discharge capacity, voltage and internal resistance of ~1.2-1.4 Ah, ~ 3.2-3.3 V, and 50-70 Ω, respectively. The cells were arranged into 4 serial and 10 parallel, to produce LIB module with the power of ~130-140 Wh, which is higher than expected.The LIB module made in Indonesia, with high local content can run the public street lighting and replace the conventional Lead Acid battery.

No abstract

While the operating voltages of Ni-Zn batteries are smaller than Li-ion batteries, Ni-Zn batteries offer some advantages, such as high specific energy and low cost. Ni-Zn batteries use green materials as they use aqueous electrolytes and do not need hazardous organic solvents. Both Ni and Zn are abundant and much less expensive in comparison to lithium. Therefore, Ni-Zn batteries are more suitable as secondary batteries for applications that do not need mobility, such as for storing electricity from solar panels at home or office building. At present, large scale usage of Ni-Zn batteries is hindered by their low life cycle due to Zn anode degradation during the operation. The Zn anode deteriorates as dendrite and passivation growth causing self-discharge at the Zn anode. Many efforts have been tried to solve those problems by adding additives in the electrode or electrolyte and a specific binder in the Zn anode. In the present work, in addition to standard CMC and PTFE as the binder in Zn anode, we also added nano-cellulose as its binder agent as the host matrix may be formed with a much smaller void, providing much more dispersion of ZnO nanoparticles and better reduction on Zn dendrite formation. The battery structures in this work were Zn-anode | electrolytes (KOH, aqueous) | Ni-cathode. Ni cathode used in this work is similar to those found in commercial Ni-Zn batteries. The Zn anode was prepared with various compositions of binder and hydroxides, such as Ca(OH)2, and ZnO nanoparticles as the active materials. The characteristics of the batteries are largely affected by the composition of the binder and other substances forming the Zn anode, particularly the proportion of the hydroxide. However, in general, the present result shows the potential of this modified Ni-Zn battery as an alternative to supersede expensive Li-ion batteries for low-cost and stationary applications.