Hydrophilic and Conductive Carbon Nanotube Fibers for High-Performance Lithium-Ion Batteries

Carbon nanotube fiber (CNTF) is a highly conductive and porous platform to grow active materials of lithium-ion batteries (LIB). Here, we prepared SnO2@CNTF based on sulfonic acid-functionalized CNTF to be used in LIB anodes without binder, conductive agent, and current collector. The SnO2 nanoparticles were grown on the CNTF in an aqueous system without a hydrothermal method. The functionalized CNTF exhibited higher conductivity and effective water infiltration compared to the raw CNTF. Due to the enhanced water infiltration, the functionalized CNTF became SnO2@CNTF with an ideal core–shell structure coated with a thin SnO2 layer. The specific capacity and rate capability of SnO2@-functionalized CNTF were superior to those of SnO2@raw CNTF. Since the SnO2@CNTF-based anode was free of a binder, conductive agent, and current collector, the specific capacity of the anode studied in this work was higher than that of conventional anodes.

Exploring Binder and Solvent for Depositing Activated Carbon Electrode on Indium–Tin-Oxide Substrate to Prepare Supercapacitors

Supercapacitor electrode slurry is prepared for mass production by mixing activated carbon powder, conductive agent, and binder, which is then deposited on a substrate using the doctor-blade method. Polyvinylidene fluoride (PVDF) and 1-methyl-2-pyrrolidone (NMP) are used as binder and solvent, respectively, to form the electrode slurry on a metal substrate. In this study, ethyl cellulose (EC) is evaluated as a binder to prepare an electrode on an indium-tin-oxide (ITO) substrate obtaining transparent supercapacitors. Terpineol and isopropyl alcohol (IPA) are compared as suitable solvents for the EC binder. When terpineol is employed as a solvent, the conductive agent is uniformly deposited around the activated carbon powder. An electrode prepared using EC and terpineol exhibits slightly lower specific capacitance and rate performance than that using conventional PVDF and NMP. However, the electrode prepared using EC and terpineol securely adheres to the electrode components, resulting in a robust electrode. In contrast, an electrode prepared using EC and IPA exhibits high charge transfer resistance at the interface of the electrode/electrolyte, leading to a low specific capacitance and rate performance. Thus, ecofriendly EC and terpineol can substitute the conventional PVDF and NMP for depositing activated carbon powder on an ITO substrate, while improving the specific capacitance of manufactured electrodes.

Experimental Study on the Effect of Conductive Carbon Black Super-P on the Properties of Composite Mortar

Conductive carbon black Super-P (CSP) is a kind of nanomaterial, which is often used as conductive agent. It has excellent conductivity and low production cost. In this paper, CSP was used as the admixture to prepare composite mortar (with the specific gravity of cementitious material). The consistency, mechanical properties, electrical conductivity and temperature sensitivity of composite mortar were studied. The mechanism of CSP was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the consistency of composite mortar decreases with the addition of CSP. The mechanical properties of composite mortar first increase and then decrease with the increase of CSP content. The addition of CSP greatly improves the conductivity of mortar. When the CSP content is 0.5–2%, the resistivity decreases rapidly and the seepage threshold appears. When the content of the mixture is large, the influence of different curing conditions on resistivity is small. SEM and XRD analysis show that CSP can fill micro pores and conduct electricity through tunnels, and does not change the composition of hydration products of composite mortar, and the formation of calcium hydroxide can be inhibited when the content is small. This paper explores the properties of CSP composite mortar, which provides theoretical and experimental basis for the preparation and application of conductive mortar.

Environmentally Friendly Route for Fabricating Conductive Agent for Lithium-Ion Batteries: Carbon Nanoparticles Derived from Polyethylene

Here, we introduce an environmentally friendly way of fabricating carbon nanoparticles which can be utilized as conductive agent for lithium-ion batteries (LIBs). Polyethylene (PE), which comprises the largest portion of plastic waste, was used as a source for carbon nanoparticle synthesis. Sulfonation allowed chemical structural transformation of innately non-carbonizable PE into a carbonizable conformation, and carbon nanoparticles could be successfully derived from sulfonated PE. Then, PE-derived carbon nanoparticles were used as conductive agents for LIBs, and assembled cells exhibited stable performance. Even though the performance is not as good as Super-P, utilization of PE as a source of conductive agent for LIBs might provide an economical advantage to upcycle PE.