Core-Shell Si@SiOC Particles Synthesized Using Supercritical Carbon Dioxide Fluid for Superior Li-Ion Storage Performance.
Rahmandhika Firdauzha Hary HernandhaBharath UmeshJagabandhu PatraChun-Yen ChenJu LiJeng-Kuei ChangPublished in: Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2024)
A supercritical carbon dioxide (SCCO 2 ) fluid, characterized by gas-like diffusivity, near-zero surface tension, and excellent mass transfer properties, is used as a precursor to produce silicon oxycarbide (SiOC) coating. SCCO 2 disperses and reacts with Si particles to form an interfacial layer consisting of Si, O, and C. After an 850 °C annealing process, a conformal SiOC coating layer forms, resulting in core-shell Si@SiOC particles. High-resolution transmission electron microscopy and its X-ray line-scan spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy, are used to examine the SiOC formation mechanism. Effects of SCCO 2 interaction time on the SiOC properties are investigated. The SiOC layer connects the Si@SiOC particles, improving electron and Li + transport. Cyclic voltammetry, galvanostatic intermittent titration technique, and electrochemical impedance spectroscopy are employed to examine the role of SiOC during charging/discharging. Operando X-ray diffraction data reveal that the SiOC coating reduces crystal size of the formed Li 15 Si 4 and increases its formation/elimination reversibility during cycling. The Si@SiOC electrode shows a capacitiy of 2250 mAh g -1 at 0.2 A g -1 . After 500 cycles, the capacity retention is 72% with Coulombic efficiency above 99.8%. A full cell consisting of Si@SiOC anode and LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode is constructed, and its performance is evaluated.
Keyphrases
- high resolution
- room temperature
- carbon dioxide
- electron microscopy
- ion batteries
- solid state
- raman spectroscopy
- single molecule
- ionic liquid
- dual energy
- computed tomography
- mass spectrometry
- single cell
- magnetic resonance imaging
- gold nanoparticles
- mesenchymal stem cells
- electron transfer
- reduced graphene oxide
- cell therapy
- dna methylation
- big data
- crystal structure
- transition metal