UPSI Digital Repository (UDRep)
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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| The objectives of this study is to synthesize lithium nickel oxide (LiNiO2) systems doped with vanadium (V) and aluminium (Al) which gives a constant and good discharge capacity for several cycles. Due to that, LiNi1-x-yAlyO2 systems were developed using carbon combustion synthesis (CCS) and solid-state reaction (SSR) method with different proportions ratio of V and Al which are x = 0.1 mole, and 0.3 mole and y = 0.1 mole. The sintering time used was 18 hours for SSR and five hours for CCS at 900°C. The first experiment is to obtain crystalline structure by x-ray diffraction analysis (XRD). The results revealed that the LiNi1-x-yVxAlyO2 are well defined hexagonal crystal system with Rd3m space group. The morphology characterization was done by using scanning electron microscopy (SEM). The SEM image for CCS samples show the presence of hexagonal structures for all the materials and it also was homogeneous. The SEM image of SSR samples showed that the particles distribution were irregular in size and also inhomogeneous when more vanadium substituted in the samples. Energy dispersive of x-ray analysis (EDAX) was done to show the percentage ratio of metals synthesized and elements and it showed the desired result. The existence of impurities NO3 - stretch appear at 1325-1450 cm-1 was confirmed from FTIR analysis. Lastly, electrochemical analysis has been done using cyclic voltammetry and charge/discharge. The cyclic voltammetry curves showed intercalation and deintercalation had occurred during testing for both methods. As conclusion, doping with vanadium and aluminium improves the discharge capacity of LiNi0.8V0.1Al0.1O2 which produced 80.57 mAh/g at the initial cycle and an average of 80.55 mAh/g for 10 cycles. The implication of this study show that doping method can improve the structural and electrochemical of the cathode materials of lithium-ion batteries. |
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