In light of the surging research on porous organic materials, we herein discuss the key issues of their porous structures, surface properties, and end functions. We also present an outlook on ...emerging opportunities, new applications, and data science-assisted materials discovery.
Electrode materials with high energy densities and long‐lasting performances are crucial to durable and reliable electrochemical energy storage devices for modern information technologies (eg, ...Internet of things). In terms of supercapacitors, their low energy densities could be enhanced by using pseudocapacitive electrodes, but meanwhile, their ultralong lifetimes are compromised by the limited charge‐discharge cycling stabilities of pseudocapacitive materials. This review article discusses on the cycling instability issues of five common pseudocapacitive materials: conjugated polymers (or conducting polymers), metal oxides, metal nitrides, metal carbides, and metal sulfides. Specifically, the article includes the fundamentals of the failure modes of these materials, as well as thoroughly surveys the design rationales and technical details of the cycling‐stability‐boosting tactics for pseudocapacitive materials that reported in the literature. Additionally, promising opportunities, future challenges, and possible solutions associated with pseudocapacitive materials are discussed.
This review article surveys the strategies of addressing the cycling instability challenges associated with pseudocapacitive materials, including conjugated polymers, metal oxides, metal nitrides, metal carbides, and metal sulfides. Additionally, the article summarizes the failure modes of these materials, explains the mechanisms of the resolutions, and discusses the opportunities for obtaining pseudocapacitive electrodes with long‐lasting charge‐storage performance.
This paper constructs a mathematical model of the C-W saving algorithm based on the characteristics of the C-W saving algorithm and the collection and data analysis of energy efficiency data of ships ...without time window constraints. On this basis, the mathematical model with the time window constraint is further constructed by adding the time window constraint and fully considering some factors in the transportation of inland vessels that cannot be ignored, such as fuel price, carbon tax price and sailing speed. Finally, the impact of fuel, charter, and carbon tax prices on the optimization scheme is analyzed by the sensitivity analysis method. With the lowest total sailing cost as the target, the total sailing cost of the whole voyage is reduced by $4,749, which is 3.75% less than last year. Optimization with the lowest carbon emission as the goal, the whole voyage CO
emissions reduced by 4.22t, a year-on-year reduction of 10.76%. Considering the total voyage cost and carbon emission for multi-objective optimization, the total voyage cost is reduced by 1210, which is 0.91% less than the same period last year. Therefore, the speed optimization method for inland sea vessels based on the C-W saving algorithm can provide a basis for shipowners and speed companies in making sailing plans.
High mass loading and fast charge transport are two crucial but often mutually exclusive characteristics of pseudocapacitors. On conventional carbon supports, high mass loadings inevitably lead to ...sluggish electron conduction and ion diffusion due to thick pseudocapacitive layers and clogged pores. Here we present a design principle of carbon supports, utilizing self-assembly and microphase-separation of block copolymers. We synthesize porous carbon fibers (PCFs) with uniform mesopores of 11.7 nm, which are partially filled with MnO
of <2 nm in thickness. The uniform mesopores and ultrathin MnO
enable fast electron/ion transport comparable to electrical-double-layer-capacitive carbons. At mass loadings approaching 7 mg cm
, the gravimetric and areal capacitances of MnO
(~50% of total mass) reach 1148 F g
and 3141 mF cm
, respectively. Our MnO
-coated PCFs outperform other MnO
-based electrodes at similar loadings, highlighting the great promise of block copolymers for designing PCF supports for electrochemical applications.
Highlights
Recent progress of active materials in supercapacitors synthesized by electrochemical techniques is reviewed.
Electrochemically synthesized nanostructures of various dimensions, ...compositions, and electrochemical properties are discussed.
The advantages and challenges of electrochemical technologies in preparing nano-/microstructured materials for electrochemical energy storage devices are summarized.
The article reviews the recent progress of electrochemical techniques on synthesizing nano-/microstructures as supercapacitor electrodes. With a history of more than a century, electrochemical techniques have evolved from metal plating since their inception to versatile synthesis tools for electrochemically active materials of diverse morphologies, compositions, and functions. The review begins with tutorials on the operating mechanisms of five commonly used electrochemical techniques, including cyclic voltammetry, potentiostatic deposition, galvanostatic deposition, pulse deposition, and electrophoretic deposition, followed by thorough surveys of the nano-/microstructured materials synthesized electrochemically. Specifically, representative synthesis mechanisms and the state-of-the-art electrochemical performances of exfoliated graphene, conducting polymers, metal oxides, metal sulfides, and their composites are surveyed. The article concludes with summaries of the unique merits, potential challenges, and associated opportunities of electrochemical synthesis techniques for electrode materials in supercapacitors.
Carbon and metal oxides are considered as the two most important categories of electrode materials for supercapacitors. To date, significant progress has been made in the synthesis of different ...carbon and metal oxide based electrodes. However, the limited ion accessible area of many carbon materials, poor electrical conductivity of most metal oxides, and sluggish ion diffusion in the bulk carbon or metal oxide materials are major barriers for these electrodes to achieve high energy density and power density simultaneously. In the past decade, numerous activation methods have been demonstrated to overcome these limitations. In this review, we summarize the recent advances in chemical methods for activating carbon and metal oxide electrodes for supercapacitors, including heteroatom doping, increasing porosity, introducing oxygen vacancies, and chemical exfoliation. The fundamentals of these methods are discussed and exemplified. We also discuss the challenges and opportunities of different activation methods.
Numerous chemical activation methods are effective in boosting the capacitive performances of carbon and metal oxide based electrodes.
A protective coating alternated with ZrB2 and MoSi2 laminated layers was designed and prepared on carbon/carbon (C/C) composites with SiC inner layer by supersonic atmosphere plasma spraying. After ...ablated at a heat flux of 2.4 MW/m2 for 30s, ZrB2/MoSi2 laminated coating was in good condition with a linear growth rate and mass gain rate of 1.67 μm/s and 0.44 mg/s, respectively. From the central region to the border region, the calculated residual thermal stress of ZrB2/MoSi2 laminated coating decreased at first and then increased rapidly, illustrating the size change of the generated laminated cracks. The alternate design of ZrB2 layers for erosion and MoSi2 layers for oxidation resulted in the laminated stress distribution and improved ablation resistance.
The development of next-generation sequencing technology has enabled researchers to explore and understand the gut microbiome from a broader and deeper perspective. However, the results of different ...studies on gut microbiota are highly variable even in the same disease, which makes it difficult to guide clinical diagnosis and treatment. The ideal sampling method should be non-invasive, involve little cross-contamination or bowel preparation, and collect gut microbiota at different sites. Currently, sequencing technologies are usually based on samples collected from feces, mucosal biopsy, intestinal fluid, etc. However, different parts of the gastrointestinal tract possess various physiological characteristics that are essential for particular species of living microbiota. Moreover, current sampling methods are somewhat defective. For example, fecal samples are just a proxy for intestinal microbiota, while biopsies are invasive for patients and not suitable for healthy controls. In this review, we summarize the current sampling methods and their advantages and shortcomings. New sampling technologies, such as the Brisbane Aseptic Biopsy Device and the intelligent capsule, are also mentioned to inspire the development of future precise description methods of the gut microbiome.
Gut microbiota dysbiosis is closely involved in intestinal carcinogenesis. A marked reduction in butyrate-producing bacteria has been observed in patients with colorectal cancer (CRC); nevertheless, ...the potential benefit of butyrate-producing bacteria against intestinal tumor development has not been fully investigated. We found that Clostridium butyricum (C. butyricum, one of the commonly used butyrate-producing bacteria in clinical settings) significantly inhibited high-fat diet (HFD)-induced intestinal tumor development in Apcmin/+ mice. Moreover, intestinal tumor cells treated with C. butyricum exhibited decreased proliferation and increased apoptosis. Additionally, C. butyricum suppressed the Wnt/β-catenin signaling pathway and modulated the gut microbiota composition, as demonstrated by decreases in some pathogenic bacteria and bile acid (BA)-biotransforming bacteria and increases in some beneficial bacteria, including short-chain fatty acid (SCFA)-producing bacteria. Accordingly, C. butyricum decreased the fecal secondary BA contents, increased the cecal SCFA quantities, and activated G-protein coupled receptors (GPRs), such as GPR43 and GPR109A. The anti-proliferative effect of C. butyricum was blunted by GPR43 gene silencing using small interfering RNA (siRNA). The analysis of clinical specimens revealed that the expression of GPR43 and GPR109A gradually decreased from human normal colonic tissue to adenoma to carcinoma. Together, our results show that C. butyricum can inhibit intestinal tumor development by modulating Wnt signaling and gut microbiota and thus suggest the potential efficacy of butyrate-producing bacteria against CRC.
•CB inhibited intestinal tumor development via modulating Wnt signaling.•CB altered gut microbiota and microbial-derived metabolites levels.•GPR43 and GPR109A were involved in the efficacy of CB.
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