Low bulk density greatly restricts the large-scale application of electrospun carbon-based fiber membrane as electrode in energy storage devices. To solve the above challenges, herein an orientation-compaction densifi...
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Low bulk density greatly restricts the large-scale application of electrospun carbon-based fiber membrane as electrode in energy storage devices. To solve the above challenges, herein an orientation-compaction densification strategy is proposed to enhance the bulk density and volumetric capacity of PAN-based carbon nanofiber membranes as self-supporting electrode used in lithium-ion batteries(LIBs). Specifically, highly-oriented fibers are achieved by high-speed roller collecting during electrospinning, and compaction densification is conducted by hot-pressing treatment. The effects of collecting speed and hot-pressing pressure on the morphology, conductivity,bulk density, tensile strength, and flexibility of the obtained carbon nanofiber membrane are *** to conventional fiber membranes, of which fibers are disorderly stacked, the oriented fiber membrane is much easier to achieve dense stacking by compaction. The obtained dense carbon nanofiber membrane demonstrates a bulk density of 0.566 g cm-3, and shows a significantly-enhanced volumetric capacity(318.3 mA h cm-3), high-rate performance(86.6 mA h cm-3at 5 A g-1), and satisfactory cycling stability when used as selfsupporting electrode of LIBs.
Single-ion conducting polymer electrolytes(SIPEs)can be formed by anchoring charge delocalized anions on the side chains of a crosslinked polymer matrix,thereby eliminating the severe concentration polarization efect ...
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Single-ion conducting polymer electrolytes(SIPEs)can be formed by anchoring charge delocalized anions on the side chains of a crosslinked polymer matrix,thereby eliminating the severe concentration polarization efect in conventional dual-ion polymer *** of a plasticizer into the polymer matrix confers advantages of both liquid and solid ***,plasticized SIPEs usually face a trade-of between conductivity and mechanical *** insufcient strength,potentially there is short-circuiting failure during *** address this challenge,a simple and mechanicallyrobust SIPE was developed by crosslinking monomer lithium(4-styrenesulfonyl)(trifuoromethylsulfonyl)imide(LiSTFSI)and crosslinker poly(ethylene glycol)diacrylate(PEGDA),with plasticizer propylene carbonate(PC),on electrospun polyacrylonitrile nanofbers(PAN-NFs).The well-fabricated polymer matrix provided fast and efective Li^(+) conductive pathways with a remarkable ionic conductivity of 8.09×10^(-4) S cm^(−1) and a superior lithium-ion transference number close to unity(t_(Li+)=0.92).The introduction of PAN-NFs not only improved the mechanical strength and fexibility but also endowed the plasticized SIPE with a wide electrochemical stability window(4.9 V ***^(+)/Li)and better cycling *** longterm lithium cycling stability and dynamic interfacial compatibility were demonstrated by lithium symmetric cell *** importantly,the assembled all-solid-state Li metal batteries showed stable cycling performance and remarkable rate capability both in low and high current ***,this straightforward and mechanically reinforced SIPE exhibits great potential in the development of advanced all-solid-state Li-metal batteries.
The lithium-ion(Li-ion)battery has received considerable attention in the field of energy conversion and storage due to its high energy density and *** academic and commercial progress has been made in Li-ion battery ...
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The lithium-ion(Li-ion)battery has received considerable attention in the field of energy conversion and storage due to its high energy density and *** academic and commercial progress has been made in Li-ion battery *** area of advancement has been the addition of nanofiber materials to Li-ion batteries due to their unique and desirable structural features including large aspect ratios,high surface areas,controllable chemical compositions,and abundant composite *** the past few decades,considerable research efforts have been devoted to constructing advanced nanofiber materials possessing conductive networks to facilitate efficient electron transport and large specific surface areas to support catalytically active sites,both for the purpose of boosting electrochemical ***,we focus on recent advancements of nanofiber materials with carefully designed structures and enhanced electrochemical properties for use in Li-ion *** synthesis,structure,and properties of nanofiber cathodes,anodes,separators,and electrolytes,and their applications in Li-ion batteries are *** research challenges and prospects of nanofiber materials in Li-ion battery applications are delineated.
The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions(ORR and OER) is critical to the practical application of zinc-air batteries(ZABs). Herein, a silica-assiste...
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The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions(ORR and OER) is critical to the practical application of zinc-air batteries(ZABs). Herein, a silica-assisted method is reported to integrate numerous accessible edge Fe-Nx sites into porous graphitic carbon(named Fe-N-G) for achieving highly active and robust oxygen electrocatalysis. Silica facilitates the formation of edge Fe-Nx sites and dense graphitic domains in carbon by inhibiting iron *** purification process creates a well-developed mass transfer channel for Fe-N-G. Consequently,Fe-N-G delivers a half-wave potential of 0.859 V in ORR and an overpotential of 344 m V at10 m A cm^(-2)in OER. During long-term operation, the graphitic layers protect edge Fe-Nx sites from demetallation in ORR and synergize with Fe OOH species endowing Fe-N-G with enhanced OER *** functional theory calculations reveal that the edge Fe-Nx site is superior to the in-plane Fe-Nx site in terms of OH* dissociation in ORR and OOH* formation in OER. The constructed ZAB based on Fe-N-G cathode shows a higher peak power density of 133 m W cm^(-2)and more stable cycling performance than Pt/C + RuO2counterparts. This work provides a novel strategy to obtain high-efficiency bifunctional oxygen electrocatalysts through space mediation.
Poly(polyol sebacate) (PPS) polymer family has been recognized as promising biomaterials for biomedical applications with their characteristics of easy production, elasticity, biodegradation, and cytocompatibility. Po...
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Poly(polyol sebacate) (PPS) polymer family has been recognized as promising biomaterials for biomedical applications with their characteristics of easy production, elasticity, biodegradation, and cytocompatibility. Poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-PEG) has been developed to fabricate PPS-based hydrogels;however, current PXS-co-PEG hydrogels presented limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. Here, we fabricate a new type of PXS-co-PEG hydrogels through the use of multifunctional crosslinkers as well as dynamic bonds. In our design, polyethyleneimine-polydopamine (PEI-PDA) macromers are utilized to crosslink aldehyde-functionalized PXS-co-PEG (APP) through imine bonds and hydrogen bonds. PEI-PDA/APP hydrogels present multiple functional properties (e.g., fluorescent, elastomeric, biodegradable, self-healing, bioadhesive, antioxidant, and antibacterial behaviors). These properties of PEI-PDA/APP hydrogels can be fine-tuned by changing the PDA grafting degrees in the PEI-PDA crosslinkers. Most importantly, PEI-PDA/APP hydrogels are considered promising wound dressings to promote tissue remodeling and prevent bacterial infection in vivo. Taken together, PEI-PDA/APP hydrogels have been demonstrated as versatile biomaterials to provide multiple tailorable properties and desirable functions to expand the utility of PPS-based hydrogels for advanced biomedical applications. Statement of significance: Various strategies have been developed to fabricate poly(polyol sebacate) (PPS)-based hydrogels. However, current PPS-based hydrogels present limited properties and functions due to the limitations of the crosslinkers and crosslinking chemistry used in the hydrogel formation. This work describes that co-engineering crosslinkers and interfacial crosslinking is a promising approach to synthesizing a new type of poly(xylitol sebacate)-co-poly(ethylene glycol) (PXS-co-
α-Zirconium phosphate(Zr(HPO_(4))_(2)⋅H_(2)O,α-ZrP)is an inorganic layered *** the first report of crystallineα-ZrP in 1964,thanks to its simple synthesis and unique physiochemical properties,α-ZrP has found wides...
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α-Zirconium phosphate(Zr(HPO_(4))_(2)⋅H_(2)O,α-ZrP)is an inorganic layered *** the first report of crystallineα-ZrP in 1964,thanks to its simple synthesis and unique physiochemical properties,α-ZrP has found widespread application in many fields including mechanical reinforcing,barrier improvement,flame retardancy,anticorrosion,catalysis,environment,energy,and *** of the ease of exfoliation ofα-ZrP to obtain single-layer nanosheets,as well as its rich surface chemistry thanks to the high density of orderly arranged surface acidic hydroxyl groups,α-ZrP single-layer nanosheets are ideal building blocks for self-assembly or assembly with other *** assembly ofα-ZrP nanosheets could form a randomly dispersed structure(isotropic),roughly ordered structure(nematic),or highly ordered structure(smectic)within liquid colloids or solid hybrids(including hydrogels).Thanks to the combination of the unique structures and the novel functions of the components,the assembled materials have found a wide verity of applications due to their excellent *** this article,the methods to synthesizeα-ZrP,the approaches and mechanisms to exfoliateα-ZrP,and the strategies to assembleα-ZrP nanosheets to form various structures,as well as the applications of the assembled materials are *** emerging prospects ofα-ZrP nanosheets as a key material in next-generation functional applications are envisioned.
Chitosan has been utilized as a popular biopolymer to fabricate hydrogels for biomedical applications. However, chitosan hydrogels are generally too brittle to mimic the deformability of the extracellular matrix in ma...
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Chitosan has been utilized as a popular biopolymer to fabricate hydrogels for biomedical applications. However, chitosan hydrogels are generally too brittle to mimic the deformability of the extracellular matrix in many tissues and organs. In particular, the role of the varied crosslinkers in determining the elasticity of chitosan hydrogels is lack of discussion. Here, three aldehyde-functionalized crosslinkers (i.e., aldehyde-modified poly(xylitol sebacate)-co-poly(ethylene glycol) (APP), glutaraldehyde (GA), and polydextran aldehyde (PDA)) are used to react with quaternized chitosan (QCS) through imine bonds to form hydrogels. The microstructures, mechanical performances, and cytocompatibility of the three hydrogels are systematically investigated. The APP/QCS hydrogels presented the best compressive and stretch properties among the three hydrogels. The mechanical property and antibacterial activity of APP/QCS hydrogels can be further modulated using varied QCS amounts, where more QCS contributed higher stiffness and stretchability as well as better bacterial inhibition to the APP/QCS hydrogels. Taken together, it is demonstrated that the inherent elastomeric characteristic of APP crosslinker provides the desirable elasticity and stretchability to QCS hydrogels compared to the other aldehyde-functionalized crosslinkers of GA and PDA. This strategy of using multivalent elastomeric crosslinkers to fabricate deformable chitosan hydrogels can expand the use of chitosan hydrogels in tissue engineering applications.
Nanocomposite (NC) hydrogels used for sonodynamic therapy (SDT) face challenges such as lacking interfacial interactions between the polymers and nanomaterials as well as presenting uneven dispersion of nanomaterials ...
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Polyvinyl alcohol(PVA)/laponite(LP)nanocomposite coatings were fabricated via a facile one-step coassembly *** formed nanocoatings contain a high concentration of LP nanosheets,which can be well aligned along the subs...
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Polyvinyl alcohol(PVA)/laponite(LP)nanocomposite coatings were fabricated via a facile one-step coassembly *** formed nanocoatings contain a high concentration of LP nanosheets,which can be well aligned along the substrate surface during the coassembly *** to the highly orientated structure,the flexible nanocoatings exhibit ultra-high transparency and superior mechanical properties,and can also act as excellent gas *** nanocoatings can be exceptional candidates for a variety of applications,such as food packaging.
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