► We observed the physical and chemical changes on the surface of carbon felts after various surface modifications. ► The surface area and chemistry of functional groups formed on the surface of ...carbon felt are critical to determine the kinetics of the redox reactions of vanadium ions. ► By incorporation of the surface modifications into the electrode preparation, the electrochemical activity of carbon felts could be notably enhanced.
The surface of carbon felt electrodes has been modified for improving energy efficiency of vanadium redox flow batteries. For comparative purposes, the effects of various surface modifications such as mild oxidation, plasma treatment, and gamma-ray irradiation on the electrochemical properties of carbon felt electrodes were investigated at optimized conditions. The cell energy efficiency was improved from 68 to 75% after the mild oxidation of the carbon felt at 500
°C for 5
h. This efficiency improvement could be attributed to the increased surface area of the carbon felt electrode and the formation of functional groups on its surface as a result of the modification. On the basis of various structural and electrochemical characterizations, a relationship between the surface nature and electrochemical activity of the carbon felt electrodes is discussed.
The electrochemical performances of 1D SnO2 nanomaterials, nanotubes, nanowires, and nanopowders, are compared to define the most favorable morphology when SnO2 nanomaterials are adopted as the ...electrode material for lithium‐ion batteries. Changes in the morphology of SnO2 are closely related with its electrochemical performance. Some SnO2 nanomaterials feature not only an increased energy density but also enhanced Li+ transfer. The correlation between the morphological characteristics and the electrochemical properties of SnO2 nanomaterials is discussed. The interesting electrochemical results obtained here on SnO2 nanomaterials indicate the possibility of designing and fabricating attractive nanostructured materials for lithium‐ion batteries.
The electrochemical performance of 1D SnO2 nanomaterials (nanotubes, nanowires, and nanopowders) can be used to define the most favorable morphology when SnO2 nanomaterials are adopted as the electrode material for lithium‐ion batteries. Changes in the morphology of SnO2 (see figure) are found to be closely related to the electrochemical performance.
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•CO and CO2 methanation was investigated over supported Ni catalysts.•Ni/CeO2 catalysts showed the highest activity.•The high-surface-area ceria provides the high Ni dispersion and ...activity.•Co-precipitated Ni0.8Ce0.2Ox catalyst showed the highest specific activity.
CO and CO2 methanation was investigated over Ni catalysts supported on different supports such as γ-Al2O3, SiO2, TiO2, CeO2, and ZrO2. Among them, Ni/CeO2 was determined to be the most active for CO and CO2 methanation. These catalytic activities increased with increasing surface area of CeO2. To increase the specific catalytic activity for CO and CO2 methanation, various Ni-CeO2 catalysts with different Ni contents were prepared using co-precipitation method. The optimum Ni content was determined for both reactions. The prepared catalysts were characterized with inductively coupled plasma-atomic emission spectroscopy, N2 physisorption, temperature-programmed reduction, temperature-programmed desorption, and X-ray diffraction. The high Ni dispersion and strong CO2 adsorption appeared to be responsible for the high catalytic activity for CO and CO2 methanation. This Ni-CeO2 can be applied to the low-temperature CO and CO2 methanation reactor to achieve high single-pass conversions of CO and CO2.
The use of solid electrolytes provides a technical solution to address the safety issues of lithium‐ion batteries and enables a bipolar design of high‐voltage and high‐energy battery modules. The ...bipolar design avoids unnecessary components and parts for packaging and electrical connection; therefore, it facilitates an increase in the volumetric energy density of the battery, while enabling easy build‐up of total output voltage. Herein, the design and construction of a multilayered, bipolar‐type, all‐solid‐state battery (ASSB) from a biphasic solid electrolyte (BSE) based on inorganic Li0.29La0.57TiO3 perovskite and poly(ethylene oxide) (PEO) are reported. A flexible and freestanding BSE membrane exhibits high Li+ conductivity of about 1.2×10−4 S cm−1, and shows enhanced electrochemical/thermal stability, in comparison to a PEO‐only solid electrolyte. A single‐layered ASSB assembled with a BSE shows promising electrochemical performance, as evidenced by a high reversible capacity of about 123 mA h g−1 and excellent cycling stability over 100 cycles. Furthermore, a proof‐of‐concept bipolar ASSB comprising three unit cells connected in series is constructed by using the BSE membrane and Al/Cu‐cladded bipolar plates. The bipolar ASSB shows high thermal stability and operates reversibly without any internal short circuit or current leakage during charge–discharge cycles; this demonstrates that BSEs provide a promising approach to the design and fabrication of bipolar ASSBs with improved safety and high energy density.
So‐solid power: A multilayered, bipolar‐type, all‐solid‐state battery is designed and constructed by using a perovskite‐based biphasic solid electrolyte (BSE). The BSE membrane exhibits high conductivity and electrochemical/thermal stability, and the bipolar battery operates reversibly without any internal short circuit or current leakage.
A high-performance Si/carbon/graphite composite in which Si nanoparticles are attached onto the surface of natural graphite by carbonization of coal-tar pitch is proposed for use in lithium-ion ...batteries. This multicomponent structure is favorable for improving Li+ storage capability because the amorphous carbon layer encapsulating Si nanoparticles offers sufficient electric conductivity and strong elasticity to facilitate relaxation of strain caused by electrochemical reaction of Si during cycles. The Si/carbon/graphite composite exhibits a specific capacity of 712 mAh g–1 at a constant current density of 130 mA g–1, and maintains more than 80% of its initial capacity after 100 cycles. Moreover, it shows a high capacity retention of approximately 88% even at a high current density of 5 C (3250 mA g–1). On the basis of electrochemical and structural analyses, we suggest that a rational design of the Si/carbon/graphite composite is mainly responsible for delivering a high reversible capacity and stable cycle performance. Furthermore, the proposed synthetic route for the Si/carbon/graphite composite is simple and cost-effective for mass production.
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•Dual-textured Prussian Blue nanocubes by controlled chemical etching.•Highly reversible Na+ storage characteristics of dual-textured PB nanocubes.•Mechanical integrity of proposed PB ...against repeated Na+ storage and extraction.
Sodium ion batteries are being highlighted as a promising energy storage system to resolve the critical issues associated with lithium ion battery usage due to a limited quantity of lithium resources on the earth. Although recent advances in sodium ion battery technology have been remarkable, the reversible capacities and cyclic performance of sodium ion batteries should be further advanced prior to their successful implementation. Herein, we demonstrate dual-textured Prussian blue nanocubes prepared via simple acid etching as a reliable sodium storage material. Taking advantage of their hybrid microstructure composed of porous and non-porous domains, dual-textured Prussian blue nanocubes exhibit high reversible capacities, good rate capabilities, and stable cyclic performance. Moreover, the nanocubes exhibit excellent dimensional stability even after 100 cycles, offering new opportunities for the development of robust and high-performance sodium rechargeable batteries.
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•Comparison of imidazolium ionic liquids (ILs) for disruption of H. pluvialis cyst.•Co-extraction of lipid and astaxanthin using room-temperature IL/water mixtures.•Very high ...astaxanthin recoveries (>99%) by IL pretreatments and hexane extractions.
Energy-saving, high-efficiency cell disruption is a critical step for recovery of thermolabile antioxidant astaxanthin from Haematococcus pluvialis cyst cells of rigid cell-wall structure. In this study, as room-temperature green solvents, 10 types of 1-ethyl-3-methylimidazolium (Emim)-based ionic liquids (ILs) were compared and evaluated for their abilities to disrupt H. pluvialis cyst cells for astaxanthin/lipid extraction. Among the 10 ILs tested, 3 Emim-based ILs with HSO4, CH3SO3, and (CF3SO2)2N anions were selected based on astaxanthin/lipid extraction performance and synthesis cost. When pretreated with IL/water mixtures, intact cyst cells were significantly torn, broken or shown to release cytoplasmic components, thereby facilitating subsequent separation of astaxanthin/lipid by hexane. However, excess IL pretreatments at high temperature/IL dosages and longer incubation times significantly deteriorated lipid and/or astaxanthin. Under optimized mild conditions (6.7% (v/v) IL in water solution, 30 °C, 60 min), almost complete astaxanthin recoveries (>99%) along with moderate lipid extractions (∼82%) could be obtained.
Silicon-based materials are the most promising candidates to surpass the capacity limitation of conventional graphite anode for lithium ion batteries. Unfortunately, Si-based materials suffer from ...poor cycling performance and dimensional instability induced by the large volume changes during cycling. To resolve such problems, nanostructured silicon-based materials with delicately controlled microstructure and interfaces have been intensively investigated. Nevertheless, they still face problems related to their high synthetic cost and their limited electrochemical properties and thermal stability. To overcome these drawbacks, we demonstrate the strategic design and synthesis of a gyroid three-dimensional network in a Si@SiO x /C nanoarchitecture (3D-Si@SiO x /C) with synergetic interaction between the computational prediction and the synthetic optimization. This 3D-Si@SiO x /C exhibits not only excellent electrochemical performance due to its structural stability and superior ion/electron transport but also enhanced thermal stability due to the presence of carbon, which was formed by a cost-effective one-pot synthetic route. We believe that our rationally designed 3D-Si@SiO x /C will lead to the development of anode materials for the next-generation lithium ion batteries.
Batteries are a promising technology in the field of electrical energy storage and have made tremendous strides in recent few decades. In particular, lithium‐ion batteries are leading the smart ...device era as an essential component of portable electronic devices. From the materials aspect, new and creative solutions are required to resolve the current technical issues on advanced lithium (Li) batteries and improve their safety. Metal‐organic frameworks (MOFs) are considered as tempting candidates to satisfy the requirements of advanced energy storage technologies. In this review, we discuss the characteristics of MOFs for application in different types of Li batteries. A review of these emerging studies in which MOFs have been applied in lithium storage devices can provide an informative blueprint for future MOF research on next‐generation advanced energy storage devices.
In this review, we discuss the characteristics of metal‐organic frameworks (MOFs) applied to lithium storage devices containing Li‐ion, Li‐sulfur, Li‐metal, and Li‐O2. We summarize the origin, nomenclature, and synthesis method of MOFs, and report on recent studies in which MOFs and MOF‐derived materials are applied to lithium rechargeable batteries. This provides an informative roadmap for next‐generation advanced energy storage devices.
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