Lithium ion batteries have important applications in various electronic devices. The use of battery components such as LiFePO4 cathodes determines battery performance. However, the electronic ...conductivity of LiFePO4 is low; therefore, increasing the conductivity of the LiFePO4 cathode sheet is very important. The aim of this research is to obtain the conductivity of LiFePO4 cathode sheet which can be applied as lithium ion battery cathode through calendaring process optimization. LiFePO4 cathode sheet preparation begins with LiFePO4 slurry (LiFePO4 + Carbon Black and PVDF / NMP) slurry, followed by coating it on Al foil surface, resulting in a sample denoted as C0. The calendaring process was then carried out to the cathode sheet, at 100°C by repeating once, twice, and three times, producing samples hereinafter referred to as C1, C2, and C3 respectively. LiFePO4 cathode sheet products are characterized with X-ray diffractometer (XRD) and scanning electron microscopy (SEM) combined with energy-dispersive spectrophotometer (EDS) and LCR-meter. The XRD pattern shows that the LiFePO4 cathode sheet consists of LiFePO4 and carbon crystal phases. The cross-sectional microstructure of the LiFePO4 cathode sheet shows that the sheets becomes denser and thinner as the number of calendaring increases. The thickness of the LiFePO4 cathode sheet decreases with increasing calendaring process. The LiFePO4 cathode sheet for the C0 sample was about 160μm in thick, and decreased gradually to 140, 130 and 120μm for the C1, C2 and C3 samples, respectively. The conductivity of the sample was improved from 9.9 × 10−5 to 2.9 × 10−5, 3.0 × 10−4, and 5.5 × 10−4 S.cm−1. The density also was improved from 2.359 to 2.516 and to 2.638 g.cm−1 with increasing calendaring process. It can be concluded that the optimizing calendaring process of the LiFePO4 cathode sheet with the LiFePO4 cathode sheet is important to improve the performance of batteries.
Research on synthesis of Li4Ti5O12 has been carried out using ultrasonic method with the objective to study the influence of the Sn addition to the materials conductivity and structure of lithium ...titanate. The starting materials used were LiOH and TiO2, while Sn was used as an additive with percentages of 0, 5%, 10%, 15% and 20%. Lithium hydroxide, titanium dioxide, and Sn were mixed into an aquabidest media and stirred for two hours at a rate of 300 rpm. Then it was reacted with the help of ultrasound for two hours, filtered and washed with distilled water and then rinsed with acetone. After drying overnight at room temperature, the resulting powder material is compacted using a hydraulic press at a pressure of 4000 psi and the obtained pellets were sintered in the furnace at 800 °C for two hours. Characterization was performed using LCR meter and X-ray diffraction (XRD) to measure the conductivity and the crystal structure, respectively. The SEM-EDS are used to observe the morphology and the composition of the material. The results of the Rietveld analysis showed that the un-doped sample correspond to cubic crystal structure with space group of Fd-3m that belong to Li4Ti5O12 and monoclinic crystal structure with space group of C12/c1 that belong to Li2TiO3. It turned out that the increase of Sn; did not change in the ratio between Li4Ti5O12 and Li2TiO3, as well as in the lattices constant for all three phases. The optimum conductivity of 6.57 × 10−6 S/cm was obtained for 5 % Sn addition to Li4Ti5O12. A more homogeneous particle distribution was observed by SEM, due to ultrasonic method. It is concluded that the Sn addition to Li4Ti5O12 has improved structural and electrical performance of the anode materials for lithium ion battery.
On quenching the molten mixture (AgI)
0.5(LiPO
3)
0.5 two different components were obtained. The first type is the clear and transparent glass, named G-(AgI)
0.5(LiPO
3)
0.5 and the second is the ...yellowish-green opaque named C-(AgI)
0.5(LiPO
3)
0.5. The X-ray diffraction data confirmed that the G-(AgI)
0.5(LiPO
3)
0.5 is an amorphous phase, with a broad peak corresponds to original LiPO
3 glass, but its conductivity increases from 10
−
8
S/cm to 10
−
6
S/cm at ambient temperature, and the glass transition temperature decreases from 327 °C to 321 °C. The composite part, C-(AgI)
0.5(LiPO
3)
0.5 consists of a mixture of amorphous background and several Bragg peaks that correspond to the crystalline AgI, but its conductivity increases from 10
−
6
S/cm to 10
−
3
S/cm at ambient temperature. The AC conductivity data at various temperatures were fit to the Non Linear Least Square Equation containing three parameters, the DC conductivity (
σ
DC), the onset frequency (
ω
p) and the exponent factor (
n). The values of
n were found to be larger than 1 for LiPO
3 and G-(AgI)
0.5(LiPO
3)
0.5 which are in agreement with earlier results, while for C-(AgI)
0.5(LiPO
3)
0.5 the
n values are between 0.5 and 0.7. The
n value really depends on the characteristic of the disorder materials and it may be due to more than one vibration that occur at the same time.
Indonesia's renewable energy systems are reducing the world's dependence on fossil fuels by providing constant energy sources such as lithium ion battery (LIB) for application on solar street lamps. ...There are advantages of using LIB that will improve its performance and life cycle, and also reduce the maintenance cost. Due to these reasons, a National Consortium on Lithium Ion Battery for Solar Street Lamp was formed in 2016 and supported by the National Innovation System (INSINAS) from the Ministry Research Technology and Higher Education. The project was divided into four work breakdown structures (WBS), with various activities and targets. The goal of this consortium is to produce a lithium ion battery module with the specification 120 Watt hour, so as to run the 10 Watt street lamp. The module consists of 40 cylinder cells 18650. The first year's target is to produce cylinder cells 18650 with specific output of 3.2 Volt and 1 Ah. This paper will review the activities of the consortium, WBS, and the characteristic of the cylinder cells.
Indonesian battery consortium for solar cell battery has made several battery prototypes and ready to be tested in a real system. Monitoring performance of battery prototype, while it is running in ...real system is necessary in order to study its behavior. The results are important to be used for improvement of the battery prototype itself. Accurate monitoring of battery performance can be obtained by fitting the instrumentation with the application and condition which are monitored. Generally the system for monitoring battery performance only measures electrical current and voltage, meanwhile for further development, it is also important to measure another variables like internal and ambient temperature of the battery pack. Therefore development of battery performance data acquisition system for monitoring battery performance inside solar cell system is acquired. Battery voltage and current will be measured using a DC voltage sensor based on voltage divider, and using non invasive current sensor WCS1800, respectively. Temperature inside battery pack and ambient temperature are measured using thermocouple type K, and BME280, respectively. All measured variables are pooled to the microcontroller and then they are transmitted to the display screen. This system is expected to be used for monitoring battery performance accurately.
The ionic conductivities of two different electrolytes, namely lithium hexafluorophosphate (LiPF6) and lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), in carbonate-based solvents have been ...investigated. The ionic conductivity of LiTFSI electrolyte is slightly larger than the LiPF6 electrolyte, namely 2.7 mS/cm vs. 2.4 mS/cm. The results of cyclic voltammetry and electrochemical impedance spectroscopy measurements show that LiTFSI electrolyte exhibit a better reversible redox reaction. Therefore, in this work, the full-cell battery using LiTFSI electrolyte exhibited higher specific capacity than the battery cell using LiPF6 electrolyte, namely 83.1 mAh/g and 101.5 mAh/g for the LiPF6 and LiTFSI electrolytes, respectively. Higher capacity in LiTFSI battery is thus related to better ionic conductivity and reversible redox reaction of LiTFSI electrolyte.
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.
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