Development of Surface‐Engineered Tape‐Casting Method for Fabricating Freestanding Carbon Nanotube Sheets Containing Fe₂O₃ Nanoparticles for Flexible Batteries

Abstract

Chemical vapor deposition and filtration are commonly used to fabricate freestanding multiwalled carbon nanotube sheets containing iron(III) oxide (Fe 2 O 3 ) (MWCNT-Fe 2 O 3 sheets). However, the former is relatively expensive, and the latter suffers from poor scalability. Here, the authors develop an inexpensive, scalable, high-throughput, tunable tape-casting method for fabricating flexible, foldable freestanding MWCNT-Fe 2 O 3 sheets. When tested as electrodes in lithium-ion batteries, the sheets perform better than conventional graphite on copper foil (681 mAh g À1 after 20 cycles at 100.5 mA g À1 /0.1 C-rate vs. 72.5 mAh g À1 after 20 cycles at 37.2 mA g À1 /0.1 C-rate). Sheets prepared at Fe 2 O 3 :MWCNT mass ratios ranging from 1/4 to 2/1 are flexible and easy to be separated from the substrate, but a sheet prepared at a 9/1 ratio is not. The ratio can be tuned to suit various applications. Sheets with high (low) Fe 2 O 3 :MWCNT mass ratios has high (low) charge-transfer resistance and are suitable for applications requiring high energy density (high power density). Mechanical compression of the sheets flattens them and increase their density from 0.449 to 0.771 g cm À3 , which in turn increases their electrical conductivity from 3.56 Â 10 3 to 5.73 Â 10 3 S m À1 .

Smooth surface induced glossy appearance of freestanding multiwall carbon nanotube sheet

“…Previously, we have reported MWCNT sheet with matt surface appearance (referred to as matt MWCNT sheet), which was made using industrially compatible roll-to-roll surface-engineered tape-cast (SETC) technique [15][16][17].…”

Robust Surface-Engineered Tape-Cast and Extrusion Methods to Fabricate Electrically-Conductive Poly(vinylidene fluoride)/Carbon Nanotube Filaments for Corrosion-Resistant 3D Printing Applications

“…The solution was exposed to ultrasonication and mechanical stirring with a VCX 750 Ultrasonic Processor (Sonic, USA) and Advanced Hotplate Stirrer (VWR, USA) for 2 min at 500 rpm and 8 min at 800 rpm while the amplitude of sonicator was set at 40%. Then the mixture was tape-casted on top of copper foil (matt-side facing up) 30–32 with 5 mm gap and dried in a convection oven (Binder Forced Convection Oven FD 53) at a temperature of 120 °C for 1 hour. After drying, the composite sheet was peeled off from copper sheet and cut into small pieces.…”

“…Figure 1 illustrates our processing method for fabrication of PVDF-MWCNT filaments for FFF. The first steps involve the mixing of PVDF powders and MWCNT flakes; and convert them to paper shape using Surface-Engineered Tape-Cast (SETC) technique 30–32 . We found that reported approach in the literature (called solution-cast) resulted in the uniform composition of PVDF-MWCNT, but was limited to ~15 wt% CNT due to high viscosity limitation during the solution-cast process 3 .…”

Design, preparation and assembly of flexible electrode based on carbon materials

“…崔屹课题组 [40] 还将Si与CNT集 合成一个整体, 制备了自支撑的CNT-Si薄膜, 其结构 类似于钢筋增强的混凝土, CNT网络即提供机械支撑, 又发挥导电作用, 而Si作为活性材料, 提供电化学容 量. 抽滤法是制备CNT柔性电极常用的方法 [41~43] , 此 外, 还有一些柔性电极的制备方法被报道, 如流延 法 [44] 、喷雾干燥法 [45] 、蒸发诱导自组装 [46] 等. 除了利用电极本身的弯折能力和多孔结构缓冲 变形应力以外, 一些特殊的电极形态也被设计出来, 控制应力.…”