Hybridizing nanostructured metal oxides with multiwalled carbon nanotubes (MWCNTs) is highly desirable for the improvement of electrochemical performance of lithium-ion batteries. Here, a facile and scalable strategy to fabricate hierarchical porous MWCNTs/Co3O4 nanocomposites has been reported, with the help of a morphology-maintained annealing treatment of carbon nanotubes inserted metal organic frameworks (MOFs). The designed MWCNTs/Co3O4 integrates the high theoretical capacity of Co3O4 and excellent conductivity as well as strong mechanical/chemical stability of MWCNTs. When tested as anode materials for lithium-ion batteries, the nanocomposite displays a high reversible capacity of 813 mAh g(-1) at a current density of 100 mA g(-1) after 100 charge-discharge cycles. Even at 1000 mA g(-1), a stable capacity as high as 514 mAh g(-1) could be maintained. The improved reversible capacity, excellent cycling stability, and good rate capability of MWCNTs/Co3O4 can be attributed to the hierarchical porous structure and the synergistic effect between Co3O4 and MWCNTs. Furthermore, owing to this versatile strategy, binary metal oxides MWCNTs/ZnCo2O4 could also be synthesized as promising anode materials for advanced lithium-ion batteries.
The solid-electrolyte interphase (SEI) layer is pivotal for the stable and rechargeable batteries especially under high rate. However, the mechanism of Li+ transport through the SEI has not been clearly...
Electrocatalytic water splitting is one of the most promising sustainable energy conversion technologies, but is limited by the sluggish electrochemical reactions. Inorganic nanomaterials have been widely used as efficient catalysts for promoting the electrochemical kinetics. Several approaches to optimize the activities of these nanocatalysts have been developed. The electronic structures of the catalysts play a pivotal role in governing the activity and thus have been identified as an essential descriptor. However, the underlying working mechanisms related to the refined electronic structures remain elusive. To establish the structure–electronic‐behavior–activity relationship, a comprehensive overview of the developed strategies to regulate the electronic structures is presented, emphasizing the surface modification, strain, phase transition, and heterostructure. Current challenges to the fundamental understanding of electron behaviors in the nanocatalysts are fully discussed.
The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.201901980. As one important electrode reaction in electrocatalytic and photoelectrochemical cells for renewable energy circulation, oxygen catalysis has attracted considerable research in developing efficient and cost-effective catalysts.Due to the inevitable formation of oxygenic intermediates on surface sites during the complex reaction steps, the surface structure dynamically evolves toward reaction-preferred active species. To date, transition metal compounds, here defined as TM-Xides, where "X" refers to typical nonmetal elements from group IIIA to VIA, including hydroxide as well, are reported as highperformance oxygen evolution reaction (OER) electrocatalysts. However, more studies observe at least exterior oxidation or amorphization of materials. Thus, whether the TM-Xides can be defined as OER catalysts deserves further discussion. This Review pays attention to recent progress on the surface reconstruction of TM-Xide OER electrocatalysts with an emphasis on the identification of the true active species for OER, and aims at disseminating the real contributors of OER performance, especially under long-duration electrocatalysis.Oxygen Evolution Reaction www.advancedsciencenews.com
The core–shell MOF templated synthesis of porous NiFe2O4@Fe2O3 nanotubes that exhibit a large reversible capacity, excellent cycling stability and superior rate capability as anode materials for Li-ion batteries.
Bumetanide has been reported to alter synaptic excitation-inhibition (E-I) balance by potentiating the action of γ-aminobutyric acid (GABA), thereby attenuating the severity of autism spectrum disorder (ASD) in animal models. However, clinical evidence of its efficacy in young patients with ASD is limited. This was investigated in the present clinical trial of 83 patients, randomised to the bumetanide group (bumetanide treatment, 0.5 mg twice daily) or the control group (no bumetanide treatment). Primary [Children Autism Rating Scale (CARS)], secondary [Clinical Global Impressions (CGI)], and exploratory [inhibitory (γ-aminobutyric acid, GABA) and excitatory (glutamate, Glx) neurotransmitter concentrations measured in the insular cortex (IC) and visual cortex (VC) by magnetic resonance spectroscopy (MRS)] outcome measures were evaluated at baseline and at the 3-month follow-up. Side effects were monitored throughout the treatment course. Compared with the control group, the bumetanide group showed significant reduction in symptom severity, as indicated by both total CARS score and number of items assigned a score ≥ 3. The improvement in clinical symptoms was confirmed by CGI. GABA/Glx ratio in both the IC and VC decreased more rapidly over the 3-month period in the bumetanide group than that in the control group. This decrease in the IC was associated with the symptom improvement in the bumetanide group. Our study confirmed the clinical efficacy of bumetanide on alleviating the core symptoms of ASD in young children and it is the first demonstration that the improvement is associated with reduction in GABA/Glx ratios. This study suggests that the GABA/Glx ratio measured by MRS may provide a neuroimaging biomarker for assessing treatment efficacy for bumetanide.
The growing demand for lithium batteries with higher energy densities requires new electrode chemistries. Lithium metal is a promising candidate as the anode material due to its high theoretical specific capacity, negative electrochemical potential and favorable density. However, during cycling, low and uneven lithium ion concentration on the surface of anode usually results in uncontrolled dendrite growth, especially at high current densities. Here we tackle this issue by using lithiophilic montmorillonite as an additive in the ether-based electrolyte to regulate the lithium ion concentration on the anode surface and thus facilitate the uniform lithium deposition. The lithiophilic montmorillonite demonstrates a pumping feature that improves the self-concentrating kinetics of the lithium ion and thus accelerates the lithium ion transfer at the deposition/electrolyte interface. The signal intensity of TFSI− shows negligible changes via in situ Raman tracking of the ion flux at the electrochemical interface, indicating homogeneous ion distribution, which can lead to a stable and uniform lithium deposition on the anode surface. Our study indicates that the interfacial engineering induced by the lithiophilic montmorillonite could be a promising strategy to optimize the lithium deposition for next-generation lithium metal batteries.
Efficient hydrogen production by water electrolysis is significant for the development of renewable energy. To date, the cost and scarcity of noble‐metal catalysts are limiting their scale‐up applications. To overcome the current challenge, high‐performance novel electrocatalysts are required to speed up the commercialization of electrolysis technology. Notably, the sluggish electrode reactions, namely, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), especially the latter, have been the main rate‐limiting factor for water splitting. Phosphate, as a new series of OER electrocatalysts, has attracted enormous attentions, owing to its unique lattice structure geometry. The phosphate group not only benefits the adsorption of water molecule but also facilitates the oxyhydrate of metal site and dissociation of water. This Minireview provides a brief summary of the recent progresses of phosphate‐based electrocatalysts, discusses the relationship between crystal structure and catalytic activity, and presents the challenges of phosphate electrocatalysts.
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