Energy storage materials are vital to the use of clean energy such as hydrogen and electrochemical energy. This paper reviews the recent progress on the application of dielectric barrier discharge ...plasma-assisted milling (P-milling), a new material synthesis method developed by ourselves, in preparing energy storage materials including Mg-based hydrogen storage materials and anode materials for lithium-ion batteries. We discuss in particular the advantages of this novel milling technique on preparing those materials and improving their energy storage performances. For Mg-based hydrogen storage materials, P-milling can realize the simultaneous rapid formation of a Mg-based solid solution and the in-situ induced catalyst MgF2, thus realizing the dual tuning of thermodynamic and kinetic properties. For anode materials of lithium-ion batteries, core-shell structures are easily formed by P-milling, and those prepared materials show higher capacities and cycling stability in comparison to those prepared by conventional ball milling (C-milling). P-milling offers a simple, cost effective and pollution-free way for preparing nano-materials or accelerating mechanochemical reactions, paving the way for large scale production of energy storage materials in the future.
•Dielectric barrier discharge plasma-assisted milling (P-milling) was developed.•P-milling was adopted to synthesize energy storage materials.•Dual tuning of the thermodynamic and kinetic properties of MgH2 is realized.•Anode materials with higher capacities and cycling stability are obtained.•P-milling is promising for large-scale industrial production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Sodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, ...its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.
Coming full circle: A facile method to regenerate NaBH4 with high yield and low cost from its hydrolytic product NaBO2 is presented. This method effectively closes the loop of NaBH4 hydrolysis and regeneration and therefore enables a wide deployment of NaBH4 for hydrogen storage.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Highlights
An overview of the recent advances in hydrogen production from light metal-based materials is presented, including hydrolysis of Mg-based alloys and hydrides, hydrolysis of Al-based alloys ...and hydrides and (catalyzed) hydrolysis/alcoholysis of borohydrides.
Hydrogen production and storage in a close loop are achieved via hydrolysis and regeneration of borohydrides, demonstrating a promising step toward the large-scale application of chemical hydrogen storage materials in a fuel cell-based hydrogen economy.
As an environmentally friendly and high-density energy carrier, hydrogen has been recognized as one of the ideal alternatives for fossil fuels. One of the major challenges faced by “hydrogen economy” is the development of efficient, low-cost, safe and selective hydrogen generation from chemical storage materials. In this review, we summarize the recent advances in hydrogen production via hydrolysis and alcoholysis of light-metal-based materials, such as borohydrides, Mg-based and Al-based materials, and the highly efficient regeneration of borohydrides. Unfortunately, most of these hydrolysable materials are still plagued by sluggish kinetics and low hydrogen yield. While a number of strategies including catalysis, alloying, solution modification, and ball milling have been developed to overcome these drawbacks, the high costs required for the “one-pass” utilization of hydrolysis/alcoholysis systems have ultimately made these techniques almost impossible for practical large-scale applications. Therefore, it is imperative to develop low-cost material systems based on abundant resources and effective recycling technologies of spent fuels for efficient transport, production and storage of hydrogen in a fuel cell-based hydrogen economy.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Lithium–sulfur (Li–S) batteries have attracted much attention in the field of electrochemical energy storage due to their high energy density and low cost. However, the “shuttle effect” of the sulfur ...cathode, resulting in poor cyclic performance, is a big barrier for the development of Li–S batteries. Herein, a novel sulfur cathode integrating sulfur, flexible carbon cloth, and metal–organic framework (MOF)‐derived N‐doped carbon nanoarrays with embedded CoP (CC@CoP/C) is designed. These unique flexible nanoarrays with embedded polar CoP nanoparticles not only offer enough voids for volume expansion to maintain the structural stability during the electrochemical process, but also promote the physical encapsulation and chemical entrapment of all sulfur species. Such designed CC@CoP/C cathodes with synergistic confinement (physical adsorption and chemical interactions) for soluble intermediate lithium polysulfides possess high sulfur loadings (as high as 4.17 mg cm–2) and exhibit large specific capacities at different C‐rates. Specially, an outstanding long‐term cycling performance can be reached. For example, an ultralow decay of 0.016% per cycle during the whole 600 cycles at a high current density of 2C is displayed. The current work provides a promising design strategy for high‐energy‐density Li–S batteries.
A flexible sulfur cathode integrating sulfur, flexible carbon cloth, and N‐doped carbon nanoarrays with embedded CoP is successfully designed. Due to the artful structure and synergistic confinement for soluble lithium polysulfides, it displays an outstanding long‐term cycling performance and an ultralow decay of 0.016% per cycle during the whole 600 cycles at 2C.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Magnesium (Mg) was coated by different transition metals (TM: Ti, Nb, V, Co, Mo, or Ni) with a grain size in the nano-scale to form a core (Mg)–shell (TM) like structure by reaction of Mg powder in ...THF solution with TMCl x . The thickness of the TM shell is less than 10 nm. TPD-MS results show the Mg–Ti sample can release hydrogen even under 200 °C. It is experimentally confirmed that the significance of the catalytic effect on dehydrogenation is in the sequence Mg–Ti, Mg–Nb, Mg–Ni, Mg–V, Mg–Co and Mg–Mo. This may be due to the decrease in electro-negativity ( χ ) from Ti to Mo. However, Ni is a special case with a high catalytic effect in spite of the electro-negativity. It is supposed that the formation of the Mg 2 Ni compound may play an important role in enhancing the hydrogen de/hydrogenation of the Mg–Ni system. It is also found that the larger the formation enthalpy, the worse the dehydrogenation kinetics.
Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics ...hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH₂ are alloying, nanostructuring, and changing the reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored reaction enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
We report a new method for few-layer graphene (FLG) preparation via plasma-assisted ball milling with carbide, nitride or oxides as ball-milling media and expandable graphite raw material. Scanning ...electron microscopy, transmission electron microscopy and Raman spectroscopy were applied to characterize the FLG. FLGs prepared by using different ball-milling media such as boron nitride (BN), tungsten carbide (WC), zinc oxide (ZnO), iron oxide (Fe2O3) and germanium oxide (GeO2) were used to determine the relationship between the FLG layer number and inductive capacity of the ball-milling media. Parameters for the synthesis of high-quality FLGs were also optimized.
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•Few-layer graphene is successfully prepared via plasma-assisted ball milling.•The number of graphene layers can be controlled by varying the ball-milling media.•The suitable inductive capacity of ball-milling media stays at 7–8.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
N-doped carbon-encapsulated ZnSe@C with uniform core-shell nanorod structure has been successfully fabricated via a self-sacrificial template route. Due to the special porous nanorods structure, this ...ZnSe@C anode effectively moderates the volume expansion, improves the electron conductivity, and thus delivers a superior rate capability and stable cycling performance for KIBs.
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•Uniform core-shell ZnSe@C was synthesized via a facile self-sacrificial route.•Such ZnSe@C anode shows superior rate capability and cycling performance.•1D carbon-encapsulated porous structure enhances the electrochemical performance.
Potassium-ion batteries (KIBs) have now stimulated considerable attention due to the widely distributed potassium salt and low cost, which become the competitive candidate for Na-/Li-ion batteries and suitable application for large-scale energy systems. Here, we have reasonably designed N-doped carbon encapsulated yolk-shell ZnSe@C anode with carbon-coated Zn2GeO4@C nanorods as the self-sacrificial template. Uniform ZnSe@C nanorods were facilely prepared by the selenidation of carbon-coated Zn2GeO4@C nanorods, which were synthesized via a simple annealing of ploydopamine-coated Zn2GeO4 nanorods. Such N-doped carbon encapsulated ZnSe@C core-shell nanorods could substantially enhance the electronic conductivity, moderate the volume expansion and provide more pathways for K+ diffusion. In detail, these ZnSe@C nanorods achieve stable galvanostatic discharge/charge performance (deliver 360 mA h g−1 at 0.2 A g−1 after 60 cycles and 204 mA h g−1 at 2.0 A g−1 over 100 repeated cycles) and superior rate capability (achieve a capacities of 389.4, 379.8, 352.2, 285.6, 226.1, and 167.5 mA h g−1 at 0.1, 0.2, 0.5, 1.0, 2.0, and 4.0 A g−1, respectively). The charge-discharge mechanism of ZnSe@C was further investigated by in-situ, ex-situ X-ray diffraction XRD and transmission electron microscopy (TEM) measurements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
MgNi-based alloys have high electrochemical capacity as anode of nickel-metal hydride (Ni/MH) battery (≥500 mAh g−1). However the capacity decay seriously in charge-discharge cycling, which is ...previously ascribed to the corrosion of Mg. To solve this problem and reveal the related mechanism, the electrochemcial properties of Mg0.50Ni0.50, Mg0.45Ti0.05Ni0.05 and Mg0.40Ti0.10Ni0.50 alloys are studied in combination with their hydrogen storage properties and microstuctural evolution during cycling. This work demonstrates the amorphous phase in milled Mg0.45Ti0.05Ni0.50 and Mg0.40Ti0.10Ni0.50 alloys has higher resistance to hydrogenation-induced crystallization than milled Mg0.50Ni0.50 alloy. Thus, they show better hydrogen absorption/desorption reversibility and contribute to the reversible electrochemical capacity. Therefore, the cycle performance of the Mg0.50Ni0.50 alloy electrodes shows obvious improvement after partially substituting Mg by Ti. The capacity retention rate increases from 24.0% (Mg0.50Ni0.50) to 55.7% (Mg0.40Ti0.10Ni0.50) after 30 cycles. In addition, the Ti addition results in the formation of TiNi phase, and thus, the alloys show better electrochemical reaction kinetics and their high-rate dischargeability (HRD) is significantly improved. At 300 mA g−1, the HRD values of Mg0.50Ni0.50, Mg0.45Ti0.05Ni0.50 and Mg0.40Ti0.10Ni0.50 alloys are 41.7%, 83.7% and 90.3%, respectively. At higher discharge current density of 1200 mA g−1, the HRD values are 26.7%, 34.8% and 46.2%, respectively.
•Ti addition enhances the stability of the amorphous phase in milled Mg–Ni alloys.•Ti addition results in the formation of TiNi catalytic phase in milled Mg–Ni alloys.•Ti addition improves the electrochemical performances of milled Mg–Ni alloys.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Poor cycling stability is one of the key scientific issues needing to be solved for Li‐ and Mn‐rich layered oxide cathode. In this paper, sodium carboxymethyl cellulose (CMC) is first used as a novel ...binder in Li1.2Ni0.13Co0.13Mn0.54O2 cathode to enhance its cycling stability. Electrochemical performance is conducted by galvanostatic charge and discharge. Structure and morphology are characterized by X‐ray diffraction, scanning electronic microscopy, high‐resolution transmission electron microscopy, and X‐ray photoelectron spectroscopy. Results reveal that the CMC as binder can not only stabilize the electrode structure by preventing the electrode materials to detach from the current collector but also suppress the voltage fading of the Li1.2Ni0.13Co0.13Mn0.54O2 cathode due to Na+ ions doping. Most importantly, the dissolution of metal elements from the cathode materials into the electrolyte is also inhibited.
Sodium carboxymethyl cellulose (CMC) is used as the binder of Li1.2Ni0.13Co0.13Mn0.54O2 cathode for lithium‐ion batteries. It can drastically suppress the capacity and voltage fading of the cathode due to its higher stickiness and the exchange of the Na+ ions in the CMC with the Li+ ions in the cathode, which can significantly stabilize its crystal structure.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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