Analysis of the Effect of Calcination Time on Microstructure, Functional Groups, and Crystal Structure of LiNiO 2 Battery Cathode Material

Battery cathode material is one of the four determinants of energy storage capacity, which is used as a power source in electronic equipment. laptops, and electric vehicles. Synthesis of the cathode material for LiNiO 2 battery with one stage co-precipitation method, and variations in calcination time of 3, 6, 9 and 24 hours with a constant temperature of 700 0 C. Microstructure observations with SEM showed an uneven and homogeneous surface. The elemental compositions of Li, and Ni were analyzed by EDXS showing that Li and Ni metal decreased with increasing calcination time. The results of the crystal structure test using an X-ray diffractometer showed that with increasing calcination time the crystallite diameter decreased, but the dislocation density increased. The micro-lattice strain increased with increasing calcination time in the planes of the Miller hkl index (102), (104), (210), (108), and (113). The FTIR spectra show that the peak at wavenumber 433 cm -1 is caused by the asymmetric stretching vibration of Li–O in LiO 6 and bending vibration of NiO 6 , namely [(Ni–O–Li)], appearing at 603 cm -1 .


INTRODUCTION
The largest nickel ore content in the world is in the form of laterite and limonite nickel ore minerals, the reserves of these mineral sources are more than 23.7% located in Indonesia, especially the islands of Sulawesi and Maluku, as well as other islands.
Until now, the largest supplier of energy in Indonesia is from fossil fuels, which are increasingly depleting.For this reason, the government has planned to provide mixed energy, one of which is new and renewable energy, such as hydroelectric power plants, wind power plants, geothermal power plants, and solar panel power plants.The Wave power plant, and so on.New renewable energy to reduce CO2, SOX, NOX emissions, which cause global warming.The Indonesian government has built a mineral processing plant for laterite nickel ore and limonite into stainless steel and lithium-ion batteries (BLI).
BLI is one of the energy storage components in electric cars that will be produced in the Sulawesi area.It requires human resources and infrastructure as well as large costs.The component that cannot be separated from the increasing demand for electrical energy is the energy storage device itself (energy storage).
Energy storage is generally known as an accumulator or battery.The most dominant type of battery is a rechargeable battery, one of which is the lithium-ion battery [1].
A lightweight, rechargeable battery.
Batteries are now widely used in all aspects of life, from cell phones to electric vehicles.
Batteries can also store large amounts of energy from renewable energy sources such as solar and wind power so that they can replace the use of fossil fuels.

Analyze crystallite structure and density of line deformities (dislocations)
The X-ray diffractogram pattern is formed from the interaction between the X-         causes the position of the element Lithium (Li) to be swapped with the element Ni 2+ so that the wrong atomic position can reduce the ability to move lithium ions and reduce the capacity of the battery.In addition, the presence of nitrate ions (NO3) can help the oxidation process from Ni 2+ to Ni 3+ so that the phenomenon of the exchange of Li and Ni elements can be inhibited [11].
Table 3 shows the value of the largest dislocation density in the Miller index (102), angle 2θ = 37.92 0 , at a calcination temperature of 700 0 C with a holding time of 24 hours, which is 2.9 lines/mm 2 .And the smallest dislocation density, the same in the    According to other researchers, the synthesized material with smaller particle size with high capacity and uniform particle size distribution improves the overall battery performance with uniform charge depth of each particle [12].

CONCLUSION
The results of calculations and analysis of the synthesis of LiNiO2 battery cathode materials, using the single-stage coprecipitation method.Crystal structure testing using XRD showed that with The main components of the battery consist of a cathode (oxidation electrode), anode (reduction electrode), electrolyte as a lithium-ion transfer medium, and a separator as an electrode separator and electrolyte transfer path.The electrode is given a current collector which has a high conductivity to flow current from or to the electrode during the charging and discharging process.In the discharge process, lithium ions move from the anode to the cathode and change chemical energy into electrical energy.For the charging process, lithium ions move from the cathode to the anode and there is a change in electrical energy into chemical energy [2].The advantages of lithium ion-based batteries are that they are the lightest metal and have the highest electrochemical potential compared to other metals.Lithium is the lightest metal element and has a very low redox potential [E(Li*/Li)=-3.04 V vs SHE)], which allows cells to have high voltages and high energy density and can provide a specific capacity of 3,600 Ah/kg.
ray beams hitting the LiNiO2(LNO) battery cathode material sample, if the LNO battery cathode material test sample has a sequential Volume 7, Number 1, May 2022 ISSN 2528-2611, e-ISSN 2528-2700 structure, then some x-ray beams will change direction at their angle depending on from the structure of the test material, the sample material for the LNO battery cathode and the wavelength of the x-ray radiation source used.For this reason, it can be determined whether an LNO battery cathode material has a high density or not, and pictures and analysis using XRD tools for testing samples of LNO battery cathode material can be seen below.How to determine the X-ray diffraction angle from the results of the LNO battery cathode material test, can be determined by the Bragg law equation, namely: nλ = 2 dhkl sin θhkl where: n = is the order of diffraction λ = wavelength of x-rays dhkl = distance between diffraction planes with millerhkl.index θ = Bragg diffraction angle for the diffraction plane From this equation, it can be seen that if the wavelength of the x-rays used is known and the angle θhkl is measured, it is possible to determine the distance between the diffraction planes dhkl.For the cubic structure the distance d of the diffraction plane is related to the lattice parameters of the crystal structure by the following equation: dhkl = where: a = lattice parameter hk = miller index field dhkl = distance between planes To determine and analyze the size/diameter of crystallites referring to the X-ray diffraction peaks of the diffractogram pattern using the Debye Scherrer equation approach which is formulated: Meanwhile, to determine the value of the lattice strain, the formula is used: To determine the value of dislocation density, the formula is used: Where: D = Diameter of crystallite ρ = Dislocation Density ԑ = Lattice Strain K = Form factor of the crystal (0.9-1) λ= Wavelength of X-rays (1,54056 ) β= Value of Full Width at Half Maximum (FWHM) (rad) θ= diffraction angle (degrees) Analyze surface morphology and chemical element composition with SEM-EDXS Observation of the surface morphology or microstructure of the LNO material samples was used with the SEM-EDXS tool.In the principle of testing the SEM-EDXS tool, two types of electrons are known, namely primary electrons and secondary electrons.The primary electron material that has high energy is usually nickel, tungsten and platinum elements as well as secondary Volume 7, Number 1, May 2022 ISSN 2528-2611, e-ISSN 2528-2700 electrons that will be captured by the detector, so that 2 types of electrons will convert the signal into an image signal.In this study, it is hoped that with variations in calcination time, optimal microstructure data will be obtained in overcoming the problem of lithium nickel dioxide compounds as the cathode material for LiNiO2 batteries.RESEARCH METHOD The implementation of this research/experiment took place in the Mechanical Engineering laboratory Faculty of Engineering, Universitas Kristen Indonesia, starting from the weighing of samples, the synthesis process, the sample molding process, and the calcination process.Variation of calcination time: 3, 6, 9, and 24 hours, and at a temperature of fixed 700 0 C. Ingredient The materials used include: compound Ni(NO3)2.6H2O,lithium hydroxide [LiOH], and egg white (a chelating agent), all materials used are of technical quality, as well as materials for complete metallography.Equipment The tools used include: a. Complete sample making equipment (press and dies, ball mill/mixer) b.Furnace (Thermoline) c.SEM-EDXS Tool d.X-ray diffractometer (XRD) e. Analytical Scales f.Complete metallographic equipment, example : grinding, polishing, and compacting.

Figure 8 .
Figure 8. Graph of the relationship of dislocation density to angle 2θ ( 0 ), variation calcination time 3, 6, 9, and 24 hours, fixed temperature 700 0 C The data obtained from the test results of crystallite diameter, micro-lattice strain, and dislocation density of the LiNiO2 battery cathode material using an X-ray diffractometer (XRD), can be seen in Figure 5, and Tables 1, 2, and 3. diffraction to angle 2θ from a variation of calcination time 3, 6, 9, and 24 hours.Also, the relationship between crystallite diameter, micro-lattice strain, and discoloration density to the Miller index plane (hkl) ie (102), (104), (210), (108), Figures 9a, and 9b below, shows the spectrum of the cathode material for LiNiO2 (LNO) batteries at calcination time variations of 6 hours, and 24 hours and a constant temperature of 700 0 C with FTIR displayed through the relationship between wavenumber and absorption value.Wavenumber is a value that indicates the type of bond and absorbance is defined as the amount of absorption carried out by compounds that have certain bonds.

Figure 9 .
Figure 9. Spectrogram of LiNiO2 battery cathode material during calcination 6 hours and a constant temperature of 700 0 C The peak of 1481 cm -1 is the absorption of the H2O bond vibration.There is no indication of other bonding from the previous hypothesis, namely the presence of impurities from other substances.From the absorption peak, it turns out that the cause of hydration of the LNO battery cathode material powder is from the bonding of the -OH hydroxyl functional group on the surface

Figure 10 .
Figure 10.Spectrogram of LiNiO2 battery cathode material during calcination 24 hours and a constant temperature of 700 0 C

Figure 11 .Figure 12 .Figure 13 .Figures 11 and 12 ,
Figure 11.Micrograph of LiNiO2 battery cathode material at a calcination time of 6 hours and a constant temperature of 700 0 C increasing calcination time the mean crystallite diameter decreased (4.8961 nm to 1.0279 nm), but the average dislocation density increased (0.0538 lines/mm 2 to 1.8629 lines/mm 2 ).And the mean microlattice strain increased (2.0857% to 15.8079%) with the Miller hkl index (102), (104), (210), (108), and (113).Where the FTIR spectrum shows the vibration mode correlated with the vibrations of the octahedral units of NiO6 and LiO6 in the wavenumber zone of 400 -700 cm -1 .Thus, the peak around 433 cm -1 is caused by the Li-O.Taken together, our experimental data help better understand the degradation processes, crystal imperfections (line defects), and inherent instability in the synthesis of LiNiO2 as a lithium battery cathode material.

Table 1 .
Relationship of hkl field, calcination