Although the LiMnO cathode can provide high nominal cell voltage, high thermal stability, low toxicity, and good safety in Li-ion batteries, it still suffers from capacity fading caused by the combination of structural transformation and transition metal dissolution. Herein, a carbon-coated LiMnO cathode with core@shell structure (LMO@C) was therefore produced using a mechanofusion method. The LMO@C exhibits higher cycling stability as compared to the pristine LiMnO (P-LMO) due to its high conductivity reducing impedance growth and phase transition.
View Article and Find Full Text PDFThe safety of Li-ion batteries is one of the most important factors, if not the most, determining their practical applications. We have found that free carbonate-based solvent molecules in the hybrid electrolyte system can cause severe safety concerns. Mixing ionic liquids with a carbonate-based solvent as the co-solvent at a fixed salt concentration of 1 M LiPF can lead to free carbonate-based molecules causing poor charge storage performance and safety concerns.
View Article and Find Full Text PDFThe microstructure of the electrodes in lithium-ion batteries (LIBs) strongly affects their gravimetric and volumetric energy and power as well as their cycle life. Especially, the effect of the microstructure in the case of next-generation Ni-rich cathode materials has not yet been investigated. A comprehensive understanding of the calendering process is therefore necessary to find an optimal level of the electrode microstructure that can enhance lithium-ion transportation, minimize plastic deformation, and improve conductivity.
View Article and Find Full Text PDFTransport phenomena and the solvation structure of lithium ions (Li) and hexafluorophosphate anions (PF) in electrolytes with different fluoroethylene carbonate (FEC) concentrations as well as the electrochemical performance and safety of Ni-rich Li-ion battery cells at the 18650 cylindrical cell level are investigated. We have found that the electrolyte with an optimized FEC concentration (25% v/v) can effectively enhance the transport property in terms of the Li transference number and contact ion pair (CIP) ratio leading to high performance and safety of practical 18650 cylindrical LIBs.
View Article and Find Full Text PDFThe charge storage mechanism of mixed cobalt oxysulphide/hydroxide materials having electrochromic properties was investigated. The cobalt oxysulphide/hydroxide materials exhibit a dual reversible redox reaction and electrochromic properties in 1 M KOH during charging and discharging.
View Article and Find Full Text PDFThe interaction between the reactive lithium metal surface and LiNO3 results in the formation of LixNOy clusters, which can protect the Li metal anode and suppress the shuttling effect of lithium polysulfides via the dipole-dipole interaction called the lithium bond.
View Article and Find Full Text PDFNickel-rich layered, mixed lithium transition-metal oxides have been pursued as a propitious cathode material for the future-generation lithium-ion batteries due to their high energy density and low cost. Nevertheless, acute side reactions between Ni and carbonate electrolyte lead to poor cycling as well as rate performance, which limits their large-scale applications. Here, core-shell like LiNiCoAlO (NCA)-carbon composite synthesized by a solvent-free mechanofusion method is reported to solve this issue.
View Article and Find Full Text PDFA 3D free-standing lithiophilic silver nanowire aerogel (AgNWA) can stop the dendritic growth of lithium metal at the initial nucleation process. The 3D structure can also suppress the infinite volume expansion of lithium during cycling. The active AgNWA scaffold can serve as a Li reservoir to compensate for the irreversible consumption of Li.
View Article and Find Full Text PDFNew insight into the influence of Li+, Na+, and K+ cations between adjacent layers of birnessite-type manganese oxides (MnOx) towards the intercalation/deintercalation charge storage mechanism as a neutral electrochemical capacitor (1 M Na2SO4) is demonstrated. These structural cations play a major role in both the kinetic electron transfer in a faradaic redox reaction and the accessibility of the compensating electrolyte ions. Li-MnOx shows the highest Mn utilization of 51% followed by Na-MnOx (40%) and K-MnOx (31%), respectively.
View Article and Find Full Text PDFA single hybrid energy conversion and storage (HECS) cell of alpha-cobalt hydroxide (α-Co(OH)) in ionic liquid was fabricated and operated under light illumination. The α-Co(OH), which is unstable in an aqueous electrolyte (i.e.
View Article and Find Full Text PDFA correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
View Article and Find Full Text PDFThe effect of the intercalated alkaline cations between the adjacent layers of multilayered manganese oxide (MnO) towards the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) was investigated. Li-MnO, Na-MnO, K-MnO, Rb-MnO, and Cs-MnO provide OER overpotentials of 1.64, 1.
View Article and Find Full Text PDFWe design the Janus-like interlayer with two different functional faces for suppressing the shuttle of soluble lithium polysulfides (LPSs) in lithium-sulfur batteries (LSBs). At the front face, the conductive functionalized carbon fiber paper (f-CFP) having oxygen-containing groups i.e.
View Article and Find Full Text PDFAlthough metal-organic frameworks (MOFs) or porous coordination polymers have been widely studied, their antimicrobial activities have not yet been fully investigated. In this work, antifungal activity of copper-based benzene-tricarboxylate MOF (Cu-BTC MOF), which is water stable and industrially interesting, is investigated against , , and . The Cu-BTC MOF can effectively inhibit the growth rate of and remarkably inhibit the spore growth of , and .
View Article and Find Full Text PDFA proton-conducting coordination polymer of anionic one-dimensional (1D) chains of Zn phosphate and protonated imidazole with the formula of [Zn(HPO)(HPO)](ImH) has been used as a novel supercapacitor material in aqueous electrolytes. This material stores charges via a proton-hopping mechanism.
View Article and Find Full Text PDFManganese dioxide (MnO) has been widely used as an active material for high-performance supercapacitors due to its high theoretical capacitance, high cycling stability, low cost, and environmental friendliness. However, the effect of its crystallographic phase on charge storage performances and mechanisms is not yet clear. Herein, MnO-based supercapacitors with different structures including nanospheres, nanorods, nanotubes, and nanosheets have been fabricated and investigated.
View Article and Find Full Text PDFCarbon black nanospheres were turned to hollow carbon nanospheres (HCNs) and were used as the conductive additive in the cathodes of Li-ion batteries (LIBs). The results show that 10 wt % HCN added to the LIB cathodes, such as LiMnO, LiCoO, LiNiMnCoO, and LiFePO, can provide significantly higher specific capacity than those using spherical carbon black. For example, a specific capacity of the LiMnO/HCN/PVDF cathode at 80:10:10 wt % with a bulk electrical conductivity of 1.
View Article and Find Full Text PDFA significant enhancement in the areal capacitance of a Co(OH) supercapacitor charged and discharged under light illumination is clearly observed, with the capacitance about two-fold higher than that operated under dark conditions. This is because Co(OH) has an energy band gap of 2.85 eV and can absorb blue light and generate photoelectrons via the photovoltaic effect, leading to high current density.
View Article and Find Full Text PDFOxidized carbon nanosheets (OCNs), produced from black carbon nanospheres and used as a conductive additive in the supercapacitor electrodes of MnO2 nanorods, can significantly improve the charge-storage performance of the symmetric MnO2-nanorod supercapacitors with a maximum specific energy of 64 W h kg(-1) and power of 3870 W kg(-1). An optimum material composition of the supercapacitor electrode finely tuned is 60 : 30 : 10 wt% of MnO2 : OCN : PVDF, respectively. Interestingly, after 5000 charge/discharge cycles, the oxidation numbers of Mn at the positive and negative electrodes of the as-fabricated supercapacitor are +3.
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