# CNT-Coated Quartz Woven Fabric Electrodes for Robust Lithium-ion Structural Batteries
## 2 Materials and Methods  
Carbon Nanotube Growth on Quartz Woven Fabric: For the confirmation of the two nanostructure-coated electrodes, CNT was grown on the quartz woven fabric via a plasma-enhanced chemical vapor deposition (PECVD). Nanoparticles were deposited via sequential steps on the woven fabric, with the Al layer functioning as a buffer, and the Fe-catalyst layer activating CNT growth. The pressure of the evaporation chamber was kept under \(2\times 10^{-6}\) Torr to prevent the oxidation of the Al layer. The metal catalysts ware successfully fabricated without breaking the vacuum pressure. The CNT growth on quartz in the PECVD chamber was carried out at 600-700 \({}^{\circ}\)C for 30 min with a flow of 100 sccm CH\({}_{4}\) as a carbon source and 10 sccm of H\({}_{2}\). The process was maintained with 320 W at a pressure of 800 mTorr, with a 13.75 MHz RF plasma as an extra energy source to enhance growth of vertically aligned CNTs.  
Material Characterization: The X-ray diffraction pattern is confirmed by X-ray diffraction (XRD, D/MAX-RB 12 KW, RIGAKU, TOXYO, JAPAN) with a wavelength of \(\lambda\) = 0.15418 nm over an angular range of \(10^{\circ}\leq 20\leq 70^{\circ}\) at a step width of 0.01 \({}^{\circ}\). Raman spectroscopy was conducted with an ARAMIS from [PERSON] Jobin Yvon using argon ion laser excited at 514 nm. The microstructure and morphology of the QWF electrodes were analyzed by scanning electron microscopy (SEM, XL30, Philips) at an acceleration voltage of 10 kV and transmission electron microscopy (TEM, Tecnai G2 F30 S-Twin, FEI) operated at 300 kV. The chemical composition of the QWF electrodes were characterized using elemental analysis (EA) and inductively conductive plasma (ICP) of the developed fabric electrodes. The carbon content in the electrodes was determined by EA (Flash 2000, Thermo Scientific). Metallic elements such as Al, Fe, and Ni were determined by ICP optical emission spectrometer (inductively coupled plasma testing machine, Thermo Scientific Co./iCAP 6300 Duo).  
Electrochemical measurements: Electrochemical tests were carried out using a 2032 coin-type half-cell with Li metal as both the counter and reference electrodes. The coin cell batteries were assembled in an Ar-gas-filled glove box with H\({}_{2}\)O content \(<\) 0.3 ppm and O\({}_{2}\) content \(<\) 0.1 ppm.  
The electrolyte was prepared by dissolving 1 M LiPF\({}_{6}\) (99.99%, Aldrich) and a mixture of ethylene carbonate and ethyl-methyl carbonate (EC-EMC) at a volume ratio of 1:1 (Panaxetec, South Korea). The glass fiber membranes (GF/D, Whatman) were used as separators with a thickness of 1.55 mm. The galvanostatic measurements were carried out in a cut-off voltage potential range from 0.01 to 2.0 V (vs. Li/Li\({}^{+}\)) using a battery cycler (WBCS3000, WonATech). For the rate capability tests, the charge-discharge rate was varied from 0.05 C to 1 C-rate at 25 \({}^{\circ}\)C in a constant-temperature convection oven. The theoretical capacity of graphite (372 mAh g\({}^{-1}\)) was used to calculate the C-rate (372 mA g\({}^{-1}\) = 1 C-rate). Electrochemical impedance spectroscopy (EIS) was performed between 100 MHz and 1 MHz at the open circuit potential of the cell, which had a signal peak-to-peak amplitude of 5 mV performed by a multi-channel battery tester (BioLogic VMP3, France).