Perpustakaan Digital ITB

The majority of energy used globally comes from fossil fuels. Usage of this fuel will release CO2 emissions. Transportation is one of the main sources that produce CO2 emissions. A transition towards electric vehicles that use lithium-ion batteries as the main energy storage has been done to tackle this issue. One of the most important components of electric vehicle batteries is the cathode. The most common cathode used right now is the NMC cathode due to its high specific capacity. This high specific capacity is associated with the rich nickel content in the cathode. However, nickel-rich NMC cathode suffers from several problems, such as capacity fading caused by the formation of microcracks in its particles. Several efforts have been made to resolve this problem. One example is elemental substitution, also known as doping, with various elements. This research aims to investigate the effect of aluminum doping on the structural and electrochemical performance of Li[Ni0.85Mn0.07Co0.08-xAlx]O2 (x = 0, 0.02, 0.04, and 0.08) / NMC cathode materials. Synthesis processes were performed to produce metal-hydroxide using coprecipitation methods. The obtained metal-hydroxide was mixed with Li(OH)·H2O and Al(OH)3·H2O. The mixed hydroxide precipitate was sintered at 450 ? for 5 hours, followed by 750 ? for 12 hours to produce the NMC cathode active materials. This active material was then coated into the current collectors to obtain the electrode sheet. The electrode sheet was prepared and assembled into a coin cell. After that, the electrochemical performance of the coin cell was measured to analyze the effect of aluminum doping on its performance. To further understand the effect of doping on its atomic level, characterization such as SEM and XRD were also carried out on the synthesized active materials. The synthesized Li[Ni0.85Mn0.07Co0.08-xAlx]O2 is successfully formed. Adding aluminum results in a decrease in initial capacity. The decrease in capacity as the doping increases is due to the high cation mixing of the doped cathode. The rate performance shows that the 4%-mol doped cathode (NMCA-4) performed better than the other sample. The higher main peak of NMCA-4 in dQ/dV curve explains this performance. Furthermore, NMCA-4 performed better after long cycles than the 8%-mol (NMA) and 2%-mol (NMCA-2) doped cathode. The overall performance of NMCA-4, aside from the improvement of the diffusivity, is also attributed to the nanorod-like primary particle found on the SEM image.