FABRICATION OF SILICON/GRAPHITIC-LIKE CARBON NITRIDE (G-C3N4) NANOCOMPOSITE ANODE FOR STABILITY OF LITHIUM-ION BATTERY

• Main Author: Tri Laksono, Basuki
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70260
• Institution: Institut Teknologi Bandung

Lithium-ion Batteries (LIBs) are secondary batteries with an outstanding combination of high energy and power density. These make LIBs have a lot of applications such as portable devices and electric vehicles. However, conventional LIBs still need a lot of improvement for high-capacity demanding applications despite their performance. One of the ways is to use silicon as an anode material with significantly higher specific energy, up to 4200 mAh/g, compared to graphite as the current anode material with a limited capacity of 372 mAh/g. However, silicon as an anode still suffers from drawbacks, such as massive volume expansion, low lithium diffusion coefficient, and low electrical conductivity. Porous carbon is doped with Nitrogen interstitially in Carbon nanostructure can enhance electronic conductivity and provide additional ion storage sites without changing the arrangement of carbon atoms in carbon nanomaterials well known as Graphitic-like Carbon Nitride (g-C3N4) which has a superb buffer layer in nanocomposites which effectively inhibits the volume expansion of silicon anode, accelerates the transfer of Lithium-ion and electrons, and provides abundant of Lithium storage sites. Furthermore, Polydiallydimethylammonium chloride (PDDA) is used as a cationic surfactant for pairing Si/ g-C3N4 composite. In this work, a silicon-based composite anode at the beginning is synthesized using ball-milling as a simple and low-cost top-down method from an n-type silicon wafer. Follow with sol-gel methods aided by a surfactant to pair silicon and g-C3N4. The as-milled silicon powder has an average size of 600 nm. As confirmed by HRTEM, the Si/ g-C3N4 composite is successfully prepared with silicon particles embedded in a nitrogen-doped carbon matrix. The cycling test shows an increased performance of the half-cell LIB with Si/g-C3N4 nanocomposite electrode compared to silicon only. Si/g-C3N4 can retain 87.09% of its initial capacity of 1943.78 mAh/g after 50 cycles. Furthermore, the Si/g-C3N4 electrode also shows a higher rate capability than the silicon-only electrode.