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Facile synthesis of thin black TiO2 ? x nanosheets with enhanced lithium-storage capacity and visible light photocatalytic hydrogen production
摘要： In combination of a facile and scalable solvothermal method and solid-phase reduction reactions, a novel two-dimensional black TiO2 ? x nanosheet (TiO2 ? x NS) with high specific surface area of 108 m2 g?1 and nearly total solar spectral absorption capability have been successfully prepared. With careful characterizations, the novel TiO2 ? x NS showed enhanced electrochemical performance and visible-light photocatalytic activity than those of their white TiO2 nanosheet (TiO2 NS) precursors. The black TiO2 ? x NS electrode delivered a reversible specific capacity of 160 mA h g?1 even after cycling at 0.5 C (1 C = 190 mA h g?1) for 300 times, which was significantly higher than the corresponding white TiO2 NS electrode (104 mA h g?1). Meanwhile, the TiO2 ? x NS also exhibited enhanced ability of visible-light photocatalytic hydrogen production than that of the white TiO2 NS. It is expected that making white TiO2 NS into black ones is an effective way to design the photocatalysts with visible light response and the anodes with long lifetime and high rate performance in lithium ion batteries. The novel black TiO2 ? x NS could find potential applications in the field of environmental management and energy storage and conversion.
关键词： Solvothermal method,Photocatalysis,Black TiO2 ? x nanosheets,Anodes
更新于2025-09-23 15:23:52
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Mechanistic insights into the phenomena of increasing capacity with cycle number: using pulsed-laser deposited MoO <sub/>2</sub> thin film electrodes
摘要： Lithium ion batteries typically lose capacity or energy storage density (i.e. capacity fading) over the course of extended cycling which can be problematic for applications and appears to be exaggerated when high current rates are used. However, in some cases fluctuations in capacity with cycle number and even increases in capacity with cycle number are noted with predominantly thin film based electrodes. Here we demonstrate the synthesis and in-depth characterisation of laser deposited MoO2 thin film anodes and its unconventional mechanism. A MoO2 electrode shows an initial capacity of 79 mA h g?1 which increases to capacities of 600 mA h g?1 at 15.8 A g?1 after 90 000 cycles. A maximum capacity of 1714 mA h g?1 was achieved in an electrode cycled at 1.5 A g?1 for over 3800 cycles, the highest recorded capacity in MoOx anodes to date. The most intriguing aspects of this work is the fact that capacity is shown to fluctuate and typically increase well above the theoretical capacity of MoO2. A combination of electrochemical cycling, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, focused ion beam milling and transmission electron microscopy at various states of cycling is used to illustrate a proposed mechanism. The mechanism illustrated is based on exfoliation of layers of MoO2 off the pulsed laser deposition (PLD) grown MoO2 electrodes during cycling that creates additional surface area and easier access for Li-ions to both adsorb to the surface and insert/react with the host material. Further features in the capacity evolution are rationalised by this mechanism and methods to control the capacity evolution are detailed. These results present a rational explanation for when an electrode undergoes a substantial increase in capacity over its extended cycling life.
关键词： pulsed laser deposition,MoO2 thin film anodes,exfoliation mechanism,Lithium ion batteries,capacity increase
更新于2025-09-12 10:27:22
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Short-Term Photovoltaic Generation Forecasting Based on LVQ-PSO-BP Neural Network and Markov Chain Method
摘要： The poor cycling stability is a tricky problem in the silicon-based lithium-ion batteries. Herein, we fabricate a three-dimension polyaniline/poly (acrylic acid)/phytic acid compound binder for the silicon anodes. In this binder, polyaniline-doped and gelated by phytic acid functions as a continuous electrically conductive network structure for the silicon anodes. Meanwhile, a high density of carboxyl groups provided by poly (acrylic acid) enhance the stability of the silicon electrodes by supplying strong binding ability with current collectors and silicon particles. Using this multifunctional binder in silicon anode, we succeed in manufacturing very long cycle life of larger than 1000 cycles at a current density of 4.2 A g?1.
关键词： Si anodes,Polymer binder,Cycle,Lithium-ion battery
更新于2025-09-11 14:15:04
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Robust Pitch on Silicon Nanolayer-Embedded Graphite for Suppressing Undesirable Volume Expansion
摘要： A significant volume expansion exhibited by high-capacity active materials upon lithiation has hindered their application as Li-ion battery anode materials. Although tremendous progress has been made in the development of coating methods that improve the stability of high-capacity active materials, suitable coating sources that are both strong and economical to use are yet to be discovered. Pitch is reported here as a promising coating source for high-capacity anodes owing to the high mechanical strength and low-cost process. Using in situ transmission electron microscopy, it is found that pitch can withstand the severe volume expansion that occurs upon Si lithiation owing to its high mechanical strength, originating from the long-range graphitic ordering. Notably, pitch-coated silicon nanolayer–embedded graphite (SG) exhibits superior capacity retention (81.9%) compared to that of acetylene-coated SG (66%) over 200 cycles in a full-cell by effectively mitigating volume expansion, even under industrial electrode density conditions (1.6 g cc?1). Thus, this work presents new possibilities for the development of high-capacity anodes for industrial implementation.
关键词： volume expansion,Si anodes,lithium ion batteries,pitch,solid electrolyte interphase
更新于2025-09-10 09:29:36
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Ag?Au‐Bimetal Incorporated ZnO‐Nanorods Photo‐Anodes for Efficient Photoelectrochemical Splitting of Water
摘要： Plasmonic Ag(cid:0) Au/ZnO nanorods (ZNRs) based photo-anodes were synthesized using a simple electrochemical route and were then evaluated for photoelectrochemical (PEC) activity. The amalgamation of Ag and Au nanoclusters broadens the UV-Vis light absorption in the range of 400 nm to 650 nm. Ag(cid:0) Au/ZNRs photo-anodes had shown photo-current density of ~ 1.4 mA cm(cid:0) 2, at a bias of 0.75 V/SCE, which is ~ 3.1 times of bare ZNRs photo-anode. Bi-metallic Ag(cid:0) Au/ZNRs based photo-anode shows the maximum photo-conversion efficiency of 0.77 % at 0.5 V/SCE, under one sun illumination. Formation of hot electrons in Ag(cid:0) Au/ ZNRs photo-anodes can be partly held responsible for the enhanced PEC activity. Au/Ag core/shell morphology evolves when a thin layer of Ag is loaded on Au nanoparticles. For an in-depth analysis on Ag(cid:0) Au incorporated ZNRs based photo-anodes and its PEC activity, a detailed characterization was carried out using physico-chemical, spectral and microscopy techniques. The analysis shows that Au in direct contact with ZnO interacts mainly with oxygen vacancies present on surface of ZnO and Ag interacts with Au for an effective electron-hole segregation process at interface and electron storage occurs in metal nanoparticles. The results suggest bi-metal incorporated ZNRs based photo-anodes can be a prospective candidate for PEC water splitting application.
关键词： Water splitting,Incident photon to current conversion efficiency (IPCE),Bi-metal photo-anodes,Electrodeposition,PEC activity
更新于2025-09-04 15:30:14