This paper presents a review of the research progress in the carbon-metal oxide composites for supercapacitor electrodes. In the past decade, various carbon-metal oxide composite electrodes have been developed by integrating metal oxides into different carbon nanostructures including zero-dimensional carbon nanoparticles, one-dimensional nanostructures (carbon nanotubes and carbon nanofibers), two-dimensional nanosheets (graphene and reduced graphene oxides) as well as three-dimensional porous carbon nano-architectures. This paper has described the constituent, the structure and the properties of the carbon-metal oxide composites. An emphasis is placed on the synergistic effects of the composite on the performance of supercapacitors in terms of specific capacitance, energy density, power density, rate capability and cyclic stability. This paper has also discussed the physico-chemical processes such as charge transport, ion diffusion and redox reactions involved in supercapacitors.

20 nm sized Co 3 O 4 nanoparticles are in-situ grown on the chemically reduced graphene oxide (rGO) sheets to form a rGO-Co 3 O 4 composite during hydrothermal processing. The rGO-Co 3 O 4 composite is employed as the pseudocapacitor electrode in the 2 M KOH aqueous electrolyte solution. The rGOCo 3 O 4 composite electrode exhibits a specific capacitance of 472 F/g at a scan rate of 2 mV/s in a twoelectrode cell. 82.6% of capacitance is retained when the scan rate increases to 100 mV/s. The rGOCo 3 O 4 composite electrode shows high rate capability and excellent long-term stability. It also exhibits high energy density at relatively high power density. The energy density reaches 39.0 Wh/kg at a power density of 8.3 kW/kg. The super performance of the composite electrode is attributed to the synergistic effects of small size and good redox activity of the Co 3 O 4 particles combined with high electronic conductivity of the rGO sheets.

A new family of anion receptors based on boron compounds has been synthesized. These compounds can be used as anion receptors in lithium battery electrolytes. This family includes various borane and borate compounds with different fluorinated aryl and fluorinated alkyl groups. When these anion receptors are used as additives in 1,2-dimethoxyethane (DME) solutions containing various lithium salts, the ionic conductivities of these solutions are greatly increased. The electrolytes tested in this study were DME solutions containing the following lithium salts: LiF, LiC1, LiBr Lii, CF3COOLi, and C2F5COOLi. Without the additive, the solubility of LiF in DME (and all other nonaqueous solvents) is very

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Multi-walled carbon nanotubes (MWCNT) have been reported to cause lung pathologies in multiple studies. However, the mechanism responsible for the bioactivity has not been determined. This study used nine different well-characterized MWCNT and examined the outcomes in vitro and in vivo. MWCNT, from a variety of sources that differed primarily in overall purity and metal contaminants, were examined for their effects in vitro (toxicity and NLRP3 inflammasome activation using primary alveolar macrophages isolated from C57Bl/6 mice). In addition, in vivo exposures were conducted to determine the inflammatory and pathogenic potency. The particles produced a differential magnitude of responses, both in vivo and in vitro, that was associated most strongly with nickel contamination on the particle. Furthermore, the mechanism of action for the Ni-contaminated particles was in their ability to disrupt macrophage phagolysosomes, which resulted in NLRP3 activation and subsequent cytokine release associated with prolonged inflammation and lung pathology.

This study examined the consequences of surface carboxylation of multiwalled carbon nanotubes (MWCNT) on bioactivity. Since commercial raw MWCNT contain impurities that may affect their bioactivity, HCl refluxing was exploited to purify raw “as-received” MWCNT by removing the amorphous carbon layer on the MWCNT surface and reducing the metal impurities (e.g. Ni). The removal of amorphous carbon layer was confirmed by Raman spectroscopy and thermogravimetric analysis. Furthermore, the HCl-purified MWCNT provided more available reaction sites, leading to enhanced sidewall functionalization. The sidewall of HCl-purified MWCNT was further functionalized with the −COOH moiety by HNO3 oxidation. This process resulted in four distinct MWCNT: raw, purified, −COOH-terminated raw MWCNT, and −COOH-terminated purified MWCNT. Freshly isolated alveolar macrophages from C57Bl/6 mice were exposed to these nanomaterials to determine the effects of the surface chemistry on the bioactivity in terms of cell viability and inflammasome activation. Inflammasome activation was confirmed using inhibitors of cathepsin B and Caspase-1. Purification reduced the cell toxicity and inflammasome activation slightly compared to raw MWCNT. In contrast, functionalization of MWCNT with the −COOH group dramatically reduced the cytotoxicity and inflammasome activation. Similar results were seen using THP-1 cells supporting their potential use for high-throughput screening. This study demonstrated that the toxicity and bioactivity of MWCNT were diminished by removal of the Ni contamination and/or addition of −COOH groups to the sidewalls.

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