Transformation of Cellulose via Two-Step Carbonization to Conducting Carbonaceous Particles and Their Outstanding Electrorheological Performance

Abstract

In this study, cellulose was carbonized in two-steps using hydrothermal and thermal carbonization in sequence, leading to a novel carbonaceous material prepared from a renewable source using a sustainable method without any chemicals and, moreover, giving high yields after a treatment at 600 °C in an inert atmosphere. During this treatment, cellulose was transformed to uniform microspheres with increased specific surface area and, more importantly, conductivity increased by about 7 orders of magnitude. The successful transition of cellulose to conducting carbonaceous microspheres was confirmed through SEM, FTIR, X-ray diffraction and Raman spectroscopy. Prepared samples were further used as a dispersed phase in electrorheological fluids, exhibiting outstanding electrorheological effects with yield stress over 100 Pa at an electric field strength 1.5 kV mm−1 and a particle concentration of only 5 wt%, significantly overcoming recent state-of-the-art findings. Impedance spectroscopy analysis showed clear interfacial polarization of this ER fluid with high dielectric relaxation strength and short relaxation time, which corresponded to increased conductivity of the particles when compared to pure cellulose. These novel carbonaceous particles prepared from renewable cellulose have further potential to be utilized in many other applications that demand conducting carbonaceous structures with high specific surface area (adsorption, catalyst, filtration, energy storage).

Constructing a Carbon-Encapsulated Carbon Composite Material with Hierarchically Porous Architectures for Efficient Capacitive Storage in Organic Supercapacitors

“…As can be seen, only two broad peaks, assigned to the (002) and (100) planes of carbon (JCPDS No. : 41-1487), were reflected, which was consistent with the original H-HPAC and other activated carbon materials [ 9 , 14 , 17 , 20 , 22 ]. In line with the possible formation mechanism for PVP hydrogel proposed in our previous study, the cross-linking reactions among the polymer chains were initiated by the coordination between potassium cations (K + ) and oxygen anions (O − ) [ 9 ].…”

Engineering Conductivity and Performance in Electrorheological Fluids Using a Nanosilica Grafting Approach

“…This value was higher for samples Glu-600 and Glu@ SiO 2 when compared to Glu@m-SiO 2 and conventional carbonized materials. 16,34 The adsorption of nitrogen for samples Glu-600 and Glu@SiO 2 took place mainly at low pressures, together with slightly open hysteresis, showing the presence of micropores with a mean pore diameter 2.17 and 2.21 nm, respectively, which is significantly lower than for the sample Glu@m-SiO 2 (19.26 nm), as displayed in Figure 3B. The abrupt increase and hysteresis in the adsorption of nitrogen of the sample Glu@m-SiO 2 indicated the presence of the mesoporous structure that fits well with the coating of the material with mesoporous silica.…”

“…Carbonaceous particles have also been widely used as a dispersed phase in ER fluids for the last decade owing to their tunable conductivity and ease of preparation. , Various particulate systems based on carbonized conducting polymers − or their derivatives , have been introduced in electrorheology, and their conductivity is commonly controlled through the carbonization temperature . Recently, novel ER fluids based on hydrothermally carbonized green source cellulose exhibiting τ y > 100 Pa at only 5 wt % of the particles have been introduced . In order to further enhance the ER performance of the ER fluids, composite particles are also of high interest as a dispersed phase in ER fluids because of the possibility to tailor the properties .…”

Semi-conducting microspheres formed from glucose for semi-active electric field-responsive electrorheological systems

“…Furthermore, in many electrorheological studies, carbonization at high temperatures is considered to be an appropriate process to obtain anhydrous ER materials with suitable conductivity, good ER performance and dielectric properties. [32][33][34][35][36][37][38] In the case of glucose, however, thermal treatment leads to very low yields of carbonized materials or even to its complete decomposition. 39 Therefore, in our presented study, the carbonization process of glucose was performed in two steps leading to high yields of prepared conducting carbonaceous particles.…”