ABSTRACT
Regardless of the superiorities of Li1.3Al0.3Ti1.7(PO4)3 (LATP), such as stability against oxygen and moisture, high ionic conductivity, and low activation energy, its practical application in all-solid-state lithium metal batteries is still impeded by the formation of ionic-resistance interphase layers. Upon contact with Li metal, electron migration from Li to LATP causes the reduction of Ti4+ in LATP. As a result, an ionic-resistance layer will be formed at the interface between the two materials. Applying a buffer layer between them is a potential measure to mitigate this problem. In this study, we analyzed the potential role of LiCl to protect the LATP solid electrolyte through a first-principle study-based density functional theory (DFT) calculation. Density-of-states (DOS) analysis on the Li/LiCl heterostructure reveals the insulating roles of LiCl in preventing electron flow to LATP. The insulating properties begin at depths of 4.3 and 5.0 Å for Li (001)/LiCl (111) and Li (001)/LiCl (001) heterostructures, respectively. These results indicate that LiCl (111) is highly potential to be applied as a protecting layer on LATP to avoid the formation of ionic resistance interphase caused by electron transfer from the Li metal anode.
ABSTRACT
Bioplastic has been widely studied in the past decades as a replacement for non-biodegradable and non-environmentally friendly plastic. One of the promising materials to produce bioplastic is cellulose. However, it is rarely used as the main component for bioplastic production. This study reports a facile process to prepare bioplastic using the pure cellulose content of Cladophora sp. algae via the hydrogel method. The effect of epichlorohydrin (ECH) concentrations as the cross-linking agent was investigated toward the biodegradability, thermal, and mechanical properties of the cellulose bioplastic obtained. The results showed that ECH concentrations affected the properties of the cellulose bioplastic produced due to the number of cross-links formed during the process. The cellulose bioplastic possessed relatively high thermal and mechanical properties. The cellulose bioplastic performed excellent biodegradability, as it was degraded by more than 40% within five days. Thus, the cellulose of Cladophora sp. algae has the potential to be developed as the main component for bioplastic application.
ABSTRACT
Oil spills in the marine environment are a rising concern due to their adverse impacts on living creatures and the environment. Hence, remediation methods have been used to remove the oil from the contaminated water. A sorbent material is considered the best method for oil spill absorption. However, commonly used commercial sorbents are made from nonrenewable and nonenvironmentally friendly materials. In this research, natural rubber foam (NRF) was used as a sorbent material with the addition of a filler, i.e., silica and a silica-lignin hybrid, to increase its oil sorption capacity and reusability. The silica and silica-lignin hybrid were extracted from rice husk waste by means of the precipitation method. The silica-lignin hybrid-filled NRF exhibited excellent hydrophobicity, with a water contact angle of 133°, and had more stable reusability compared to unfilled NRF and silica-filled NRF. In addition, the optimum oil absorption capacity of silica-lignin hybrid-filled NRF was 1.36 g g-1. Overall, the results showed that silica-lignin hybrid-filled NRF has the potential to be developed as a green oil absorbent material and is promising in terms of economic and environmental aspects.
ABSTRACT
The effect of pre-treating graphite sheets in a H2SO4/H2O2 solution before electro-exfoliation is reported. It was revealed that the volume fraction of H2SO4 to H2O2 during pre-treatment could control the degree of exfoliation of the resulting exfoliated graphite (EG). X-ray diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy analyses have suggested that EG produced by first pre-treating the graphite sheet in H2SO4/H2O2 solution with the H2SO4 : H2O2 volume fraction of 95 : 5 demonstrates the highest exfoliation degree. This sample also demonstrated excellent electrochemical properties with good electrical conductivity (36.22 S cm-1) and relatively low charge transfer resistance (R ct) of 21.35 Ω. This sample also showed the highest specific capacitance of all samples, i.e., 71.95 F g-1 at 1 mV s-1 when measured at a voltage range of -0.9 to 0 V. Further measurement at an extended potential window down to -1.4 V revealed the superior specific capacitance value of 150.69 F g-1. The superior morphology characteristics and the excellent electrical properties of the obtained EG are several reasons behind its exceptional properties. The pre-treatment of graphite sheets in H2SO4/H2O2 solution allegedly leads to easier and faster exfoliation. The faster exfoliation is allegedly able to prevent massive oxidation, which frequently induces the formation of graphite/graphene oxide (GO) in a prolonged process. However, too large H2O2 volume fraction involved during pre-treatment seems to cause excessive expansion and frail structure of the graphite sheets, which leads to an early breakdown of the structure during electrochemical exfoliation and prohibits layer by layer exfoliation.
