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1.
J Colloid Interface Sci ; 667: 470-477, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38648703

RESUMO

The carbon nanomaterials are usually used to improve the electrical conductivity and stability of silicon (Si) anodes for lithium-ion batteries. However, the Si-based composites containing carbon nanomaterials generally show large specific surface area, leading to severe side reactions that generate large amounts of solid electrolyte interphase films. Herein, we embedded graphene oxide (GO) and silicon nanoparticles (Si NPs) uniformly in pitch matrix by solvent dispersion. The internally doped GO reduces the exposed surface and improves the electrical conductivity of the composite. Meanwhile, the multi-interface structures are constructed inside to limit the domains of Si NPs and improve the structural stability of the material. When evaluated as anodes, the Si/graphene/pitch-based carbon composite anode exhibits the outstanding electrochemical properties, delivering a reversible capacity of 820.8 mAh/g at 50 mA g-1, as well as a capacity retention of 93.6 % after 1000 cycles at 2 A/g. In addition, when assembled with the LiFePO4 cathode, the full cell exhibits an impressive capacity retention of 95 % after 100 cycles at 85 mA g-1. This work provides a valuable design concept for the development of Si/carbon anodes.

2.
ACS Nano ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38652811

RESUMO

Closed pores play a crucial role in improving the low-voltage (<0.1 V) plateau capacity of hard carbon anodes for sodium-ion batteries (SIBs). However, the lack of simple and effective closed-pore construction strategies, as well as the unclear closed-pore formation mechanism, has severely hindered the development of high plateau capacity hard carbon anodes. Herein, we present an effective closed-pore construction strategy by one-step pyrolysis of zinc gluconate (ZG) and elucidate the corresponding mechanism of closed-pore formation. The closed-pore formation mechanism during the pyrolysis of ZG mainly involves (i) the precipitation of ZnO nanoparticles and the ZnO etching on carbon under 1100 °C to generate open pores of 0.45-4 nm and (ii) the development of graphitic domains and the shrinkage of the partial open pores at 1100-1500 °C to convert the open pores to closed pores. Benefiting from the considerable closed-pore content and suitable microstructure, the optimized hard carbon achieves an ultrahigh reversible specific capacity of 481.5 mA h g-1 and an extraordinary plateau capacity of 389 mA h g-1 for use as the anode of SIBs. Additionally, some in situ and ex situ characterizations demonstrate that the high-voltage slope capacity and the low-voltage plateau capacity stem from the adsorption of Na+ at the defect sites and Na-cluster formation in closed pores, respectively.

3.
ACS Nano ; 17(23): 23965-23976, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37975807

RESUMO

Utilizing nanoseeds guiding homogeneous deposition of lithium is an effective strategy to inhibit disorderly growth of lithium, where silicon oxide has been attracting attention as a transform seed. However, the research on silicon-oxide-based seeds has concentrated more on utilizing their lithiophilicity but less on their Si-O structures, which could result in different failure mechanisms. In this study, various Si-O structures of silicon oxycarbide carbon nanofibers are prepared by adjusting the content of octa(aminopropylsilsesquioxane). According to XANES and experimental observations, the C-rich SiOC has an active Si-O-C structure but generates a larger volume variation during lithiation, while in the O-rich phase, the silica-oxygen tetrahedral structure can contribute to alleviate the volume expansion but has poor electrochemical activity. SiOC, which is dominated by SiO3C, has a suitable Si-O and silica-oxygen tetrahedral-structure distribution, which balances the electrochemical activity and volume expansion. This allows the host to demonstrate an excellent lifespan over 3740 h with a tiny voltage hysteresis (22 mV) at 2 mA cm-2, and it retains a favorable capacity of 97 mA h g-1 after 630 cycles with a high Coulombic efficiency of 99.7% in full cells. This study experiences the influence of various Si-O structures on lithium metal anodes.

4.
Small ; 19(41): e2302388, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37312396

RESUMO

A promising anode material for Li-ion batteries, silicon (Si) suffers from volume expansion-induced pulverization and solid electrolyte interface (SEI) instability. Microscale Si with high tap density and high initial Coulombic efficiency (ICE) has become a more anticipated choice, but it will exacerbate the above issues. In this work, the polymer polyhedral oligomeric silsesquioxane-lithium bis (allylmalonato) borate (PSLB) is constructed by in situ chelation on microscale Si surfaces via click chemistry. This polymerized nanolayer has an "organic/inorganic hybrid flexible cross-linking" structure that can accommodate the volume change of Si. Under the stable framework formed by PSLB, a large number of oxide anions on the chain segment preferentially adsorb LiPF6 and further induce the integration of inorganic-rich, dense SEI, which improves the mechanical stability of SEI and provides accelerated kinetics for Li+ transfer. Therefore, the Si4@PSLB anode exhibits significantly enhanced long-cycle performance. After 300 cycles at 1 A g-1 , it can still provide a specific capacity of 1083 mAh g-1 . Cathode-coupled with LiNi0.9 Co0.05 Mn0.05 O2 (NCM90) in the full cell retains 80.8% of its capacity after 150 cycles at 0.5 C.

5.
Small ; 19(43): e2303294, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37356060

RESUMO

The uncontrollable growth and uneven nucleation of lithium metal can be addressed by utilizing spatial confinement structures in conjunction with lithiophilic sites. However, their complex fabrication technique and the inhomogeneous dispersion of lithiophilic sites make the application ineffective. In this work, ultra-uniformly dispersed SiOx seeds and defects are produced in situ to achieve the spatially restricted protection within the reduced graphene oxide (rGO) layer. The in situ formed SiOx and defects during annealing double constrain lithium nucleation and growth behaviors thanks to the superlithiophilic characteristic, while both provide the fast Li+ transport channel to utilize the interlayer protection of rGO in limiting lithium dendrite growth. Furthermore, XANES and XPS analyze the SiOx seeds that are dominated by various valence states, and theoretical calculations further verify the control on the nucleation of lithium atoms. Benefiting from the optimum average valence of three for the "control site", the host realizes steady circulation. In asymmetric cells, the host demonstrates excellent coulombic efficiency of 99.1% and stable lifespans over 1250 h at 1 mA cm-2 . When assembled in LiFePO4 full cells, it retains a favorable capacity of 116.2 mA h g-1 after 170 cycles.

6.
Nanomaterials (Basel) ; 13(11)2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37299691

RESUMO

Lithium metal batteries (LMBs) are a dazzling star in electrochemical energy storage thanks to their high energy density and low redox potential. However, LMBs have a deadly lithium dendrite problem. Among the various methods for inhibiting lithium dendrites, gel polymer electrolytes (GPEs) possess the advantages of good interfacial compatibility, similar ionic conductivity to liquid electrolytes, and better interfacial tension. In recent years, there have been many reviews of GPEs, but few papers discussed the relationship between GPEs and solid electrolyte interfaces (SEIs). In this review, the mechanisms and advantages of GPEs in inhibiting lithium dendrites are first reviewed. Then, the relationship between GPEs and SEIs is examined. In addition, the effects of GPE preparation methods, plasticizer selections, polymer substrates, and additives on the SEI layer are summarized. Finally, the challenges of using GPEs and SEIs in dendrite suppression are listed and a perspective on GPEs and SEIs is considered.

7.
ACS Appl Mater Interfaces ; 15(2): 3006-3016, 2023 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-36601866

RESUMO

Zn-ion capacitors are attracting great attention owing to the abundant and relatively stable Zn anodes but are impeded by the low capacitance of porous carbon cathodes with insufficient energy storage sites. Herein, using ball-milled graphene with different defect densities as the models, we reveal that the self-doping defects of carbon show a capacitive energy storage behavior with robust charge-transfer kinetics, providing a capacitance contribution of ca. 90 F g-1 per unit of defect density (AD/AG value from Raman spectra) in both aqueous and organic electrolytes. Furthermore, a simple NaCl-assisted ball-milling method is developed to prepare novel graphene blocks (BSG) with abundant self-doping defect density, enriched pores, balanced electric conductivity, and high compact density (0.83 g cm-3). The optimized ion and electron transfer paths promote efficient utilization of the self-doping defects in BSG, contributing to improved gravimetric and volumetric capacitance (224 F g-1/186 F cm-3 at 0.5 A g-1) and remarkable rate performance (52.2% capacitance retention at 20 A g-1). The defect engineering strategy may open up a new avenue to improve the capacitive performance of dense carbons for Zn-ion capacitors.

8.
Small ; 19(17): e2207167, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36703536

RESUMO

Because of its high specific capacity, the silicon-graphite composite (SGC) is regarded as a promising anode for new-generation lithium-ion batteries. However, the frequently employed two-section preparation process, including the modification of silicon seed and followed mixture with graphite, cannot ensure the uniform dispersion of silicon in the graphite matrix, resulting in a stress concentration of aggregated silicon domains and cracks in composite electrodes during cycling. Herein, inspired by powder engineering, the two independent sections are integrated to construct multistage stable silicon-graphite hybrid granules (SGHGs) through wet granulation and carbonization. This method assembles silicon nanoparticles (Si NPs) and graphite and improves compatibility between them, addressing the issue of severe stress concentration caused by uncombined residue of Si NPs. The optimal SGHG prepared with 20% pitch content exhibits a highly reversible specific capacity of 560.0 mAh g-1 at a current density of 200 mA g-1 and a considerable stability retention of 86.1% after 1000 cycles at 1 A g-1 . Moreover, as a practical application, the full cell delivers an outstanding capacity retention of 85.7% after 400 cycles at 2 C. The multistage stable structure constructed by simple wet granulation and carbonization provides theoretical guidance for the preparation of commercial SGC anodes.

9.
ACS Appl Mater Interfaces ; 15(1): 1934-1943, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36573627

RESUMO

Lithium (Li) metal is a candidate anode for the next generation of high-energy density secondary batteries. Unfortunately, Li metal anodes (LMAs) are extremely reactive with electrolytes to accumulate uncontrolled dendrites and to generate unwanted parasitic electrochemical reactions. Much attention has been focused on carbon materials to address these issues. Ulteriorly, the failure mechanism investigation of lithiophilic sites on carbon materials has been not taken seriously. Herein, we design a new type of sesame ball-like carbon sphere (AgNPs@CS, an average diameter of ∼700 nm) with uniformly interfacial anchored silver nanoparticles (AgNPs), which is used as the dendrite-free Li metal anode host. This anchored structure significantly enhances reversible and chemical affinity of Li, effectively inhibiting "dead Li". In addition, the protective effect of the carbon layer can avoid the damage of lithiophilic AgNPs in the carbon matrix. With a plating/striping capacity of 2 mA h cm-2, the AgNPs@CS electrode can be cycled over 2400 h at 0.5 mA cm-2. When the stripping voltage increases to 1 V, the AgNPs@CS electrode also enables excellent cycling stability to achieve over 260 cycles (1 mA cm-2, 1 mA h cm-2) and 130 cycles (2 mA cm-2, 1 mA h cm-2). This material by electrochemical characterization highlights the efficacy of this facile method for developing dendrite-free LMAs.

10.
Nanomaterials (Basel) ; 12(21)2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36364702

RESUMO

Metal-organic frameworks (MOFs) have attracted extensive attention as precursors for the preparation of carbon-based materials due to their highly controllable composition, structure, and pore size distribution. However, there are few reports of MOFs using p-phenylenediamine (pPD) as the organic ligand. In this work, we report the preparation of a bimetallic MOF (CoCu-pPD) with pPD as the organic ligand, and its derived hollow carbon spheres (BMHCS). CoCu-pPD exhibits a hollow spherical structure assembled by nanosheets. BMHCS inherits the unique hollow spherical structure of CoCu-pPD, which also shows a large specific surface area and heteroatom doping. When using as the anode of sodium-ion batteries (SIBs), BMHCS exhibits excellent cycling stability (the capacity of 306 mA h g-1 after 300 cycles at a current density of 1 A g-1 and the capacity retention rate of 90%) and rate capability (the sodium storage capacity of 240 mA h g-1 at 5 A g-1). This work not only provides a strategy for the preparation of pPD-based bimetallic-MOFs, but also enhances the thermal stability of the pPD-based MOFs. In addition, this work also offers a new case for the morphology control of assembled carbon materials and has achieved excellent performance in the field of SIBs.

11.
Phys Chem Chem Phys ; 24(43): 26356-26370, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36286554

RESUMO

Lithium (Li) metal is strongly considered to be the ultimate anode for next-generation high-energy-density rechargeable batteries due to its lowest electrochemical potential and highest specific capacity. However, Li metal anode has limitations, involving inevitable dendritic Li growth, nonuniform Li deposition, enormous volume expansion, and ultimate electrode pulverization, which lead to rapid decrease in Coulombic efficiency and short circuits, significantly hindering its practical use. Various strategies have been proposed to solve uncontrollable dendritic Li growth and parasitic electrochemical reactions. Carbon materials and their composites with excellent structure tunability and properties have been explored to solve these issues and have shown great potential applications in Li metal anodes. This review presents various protective strategies of Li metal anode based on carbon materials. The rational design of carbon materials with specific functionalities in Li metal anode protecting solutions and manufacturing methods of composite electrodes with metallic Li and carbon materials are discussed in detail. In addition, a comprehensive understanding of the challenges and our outlook on the future development of carbon materials for stabilizing Li metal anodes in practical applications are discussed and prospected.

12.
J Colloid Interface Sci ; 628(Pt A): 975-983, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-35964444

RESUMO

S doping is an effective strategy to improve the potassium-ion storage performance of carbon-based materials. However, due to the large atomic radius of S and poor thermal stability, it is challenging to synthesize carbon materials with high sulfur content by solid-phase transformation. In this work, we designed a multi-cavity structure that can confine the molten S during heat treatment and make it fully react, then achieving high S doping (7.6 at. %). As we known, S doping can also effectively increase the active sites of carbon materials to obtain higher capacity. In addition, through different ex/in-situ characterizations and DFT calculations, we confirmed that the S atoms can effectively expand the interlayer spacing of carbon, which facilitates the intercalation/deintercalation reaction of K+, thereby significantly improving the rate performance. Therefore, benefiting from the effect of S-doping, the sample exhibits high reversible specific capacity (401.0 mAh g-1 at 0.1 A/g) and rate performance (167.2 mAh g-1 at 5 A/g). The as-assembled K+ hybrid capacitor delivers both high energy density and power density (138.5 W h kg-1 and 7692.5 W kg-1, respectively). This work provides a new approach to design S content carbon-based materials for high performance K+ storage.

13.
J Colloid Interface Sci ; 627: 783-792, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35878467

RESUMO

Lithium metal is considered as a promising anode material for next-generation secondary batteries, owing to its high theoretical specific capacity (3860 mA h g-1). Nevertheless, the practical application of Li in lithium metal batteries (LMBs) is hampered by inhomogeneous Li deposition and irreversible "dead Li", which lead to low coulombic efficiency (CE) and safe hazards. Designing unique lithiophilic structure is an efficient strategy to control Li uniformly plating /stripping. Here, we report the silver (Ag) nanoparticles coated with nitrogen-doped onion-like carbon microspheres (Ag@NCS) as a host to reduce the nucleation overpotential of Li for dendrite-free LBMs. The Ag@NCS were prepared by a simple one-step injection pyrolysis. The lithiophilic Ag is demonstrated to be priority selective deposition of Li in the carbon cage. Meanwhile, the onion-like structure benefits to uniform lithium nucleation and dendrite-free lithium during cycling. Impressively, we successfully captured lithium metal on different hosts at atomic scale, further proving that Ag@NCS can effectively and uniformly deposit Li. Besides, Ag@NCS show a superiorly electrochemical performance with a low nucleation overpotential (∼1 mV), high CE and stable cycling performance (over 400 cycles at 0.5 mA cm-2) compared to the Ag-free onion-like carbon in LMBs. Even under harsh conditions (1 mA cm-2, 4 mA h cm-2), Ag@NCS still present superior cycling stability for more than 150 cycles. Furthermore, a full cell composed of LiFePO4 cathode exhibits significantly improved voltage hysteresis with low voltage polarization. This work provides a new choice and route for the design and preparation of lithiophilic host materials.

14.
J Colloid Interface Sci ; 623: 77-85, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35569225

RESUMO

Metal-organic frameworks (MOFs) have emerged as promising precursors to prepare porous carbons due to their unique coordination structure with abundant pores and various chemical compositions. However, the structural collapse and pore shrinkage during pyrolysis severely decrease the surface area of the prepared porous carbons. Herein, we propose an inner support strategy to prepare MOF-derived carbons with improved surface area using graphene quantum dots (GQDs) as the compatible frameworks. GQDs with abundant carboxyl groups (-COOH) and rigid structure can uniformly distribute in MOF-5 precursor by coordinating with [Zn4O]6+ clusters and effectively reinforce the carbon skeleton during pyrolysis. Therefore, the rational GQDs embedded MOF-5 derived porous carbon (GMPC-0.35) shows greatly improved specific surface area (1841 m2 g-1) and mesopore volume (1.62 cm3 g-1) than pure MOF-5 derived carbon (1358 m2 g-1, 0.59 cm3 g-1). As an application exemplification, GMPC-0.35 performs high specific capacitance of 200 F g-1 at 1 A g-1 and good capacitance retention of 53% at 100 A g-1 as the electrode material for supercapacitors, which are higher than most of the reported MOF-5 derived carbons. Therefore, the compatible GQDs support is promising for preparing functional MOF-derived carbon materials.

15.
J Colloid Interface Sci ; 620: 284-292, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35429707

RESUMO

Sodium alginate (SA) is an environment-friendly and low-cost polysaccharide carbohydrate extracted from seaweed. As a carbon precursor, sodium alginate has the advantages of clear molecular structure, small molecular weight, and easy controls of the structure and composition of the product, but there have been few studies for the mechanism for SA carbonization. In this work, the carbon skeleton cross-linking mode, heteroatom doping and defect generation mechanism in the process of SA pyrolysis are clarified. Subsequently, based on the understanding of the carbonization mechanism of SA-derived carbon, we have prepared a stable SA-derived interconnected porous carbon by self-template method. The materials prepared by this method possess high oxygen content (17.6 at%) and high specific surface area (384.4 m2 g-1). Zn-ion hybrid capacitors (ZICs) device assembled with SA-derived porous carbon performs superior energy densities (based on cathode mass) of 78.35 and 35.56 Wh kg-1 at the power densities of 160 and 5120 W kg-1, respectively. This work deeply explained the carbonization mechanism of sodium alginate and evaluated the application prospects of SA-based carbon in ZICs comprehensively.


Assuntos
Alginatos , Carbono , Carbono/química , Eletrodos , Íons , Porosidade
16.
J Colloid Interface Sci ; 620: 168-178, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35421753

RESUMO

With the development of various flexible electronic devices, flexible energy storage devices have attracted more research attention. Binder-free flexible batteries, without a current collector, binder, and conductive agent, have higher energy density and lower manufacturing costs than traditional sodium-ion batteries (SIBs). However, preparing binder-free anodes with high electrochemical performance and flexibility remains a great challenge. In this study, a binary self-assembly composite of an ordered Bi4Se3/Bi2O2Se lamellar architecture wrapped by carbon nanotubes (CNTs) was embedded in graphene with strong interfacial interaction to form Bi2O2Se/Bi4Se3@CNTs@rGO (BCG), which was used as a binder-free anode for SIBs. A unique "one-changes-into-two" phenomenon was observed: the layered Bi2Se3 was transformed into a unique layered Bi4Se3/Bi2O2Se heterojunction structure, which not only provides more electrochemical channels but also reduces internal stress to improve the stability of the material structure. BCG-2 showed excellent sodium-ion storage, delivering a reversible capacity of 346 mA h/g at 100 mA/g and maintaining a capacity of 235 mA h/g over 50 cycles. Even at a high current density of 1 A/g, it retains a capacity of 105 mA h/g after 1000 cycles. This unique design concept can also be employed in synthesizing other binder-free electrodes to improve their properties.

17.
J Colloid Interface Sci ; 620: 24-34, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35405563

RESUMO

Heteroatom-rich carbon materials deliver superior potassium storage capacity owing to the abundant active sites, but their stability and conductivity are damaged because of the numerous defects and distortion of π-conjugated system. In this work, we amended the adverse influences of heteroatoms on carbon materials through the B, N stabilization effect. Due to an amending effect of B atoms on the N-doped carbon matrix, the integrity of the carbon skeleton and stability of the system are significantly enhanced, and the undesirable defects are transformed into favorable active sites, resulting in the simultaneous improvement of K+ storage capacity, rate performance and cyclic stability. The stabilized materials have a highly reversible carbon structure and fast K+ transfer kinetics, leading to high reversible capacity (300 mA h g-1 at 0.1 A g-1), good rate performance (107.2 mA h g-1 at 10 A g-1) and superior cyclic stability (75.3 % capacity retention from cycle 11 to 2000 at 1 A g-1). Consequently, the constructed devices perform excellent energy densities of 158.8 and 40.7 Wh kg-1 under power densities of 100 and 11250 W kg-1, respectively. This work proposes an effective strategy for significantly improving heteroatom-rich carbon materials, which broadens its application fields in high-performance potassium ion storage.


Assuntos
Carbono , Potássio , Condutividade Elétrica , Íons , Microesferas , Potássio/química
18.
Small ; 18(16): e2105738, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35253978

RESUMO

Fast charging rate and large energy storage are key requirements for lithium-ion batteries (LIBs) in electric vehicles. Developing electrode materials with high volumetric and gravimetric capacity that could be operated at a high rate is the most challenging problem. In this work, a general multi-interface strategy toward densified carbon materials with enhanced comprehensive electrochemical performance for Li/Na-ion batteries is proposed. The mixture of graphene oxide and sucrose solution is sprayed into a water/oil system and furtherly carbonized to get graphene/hard carbon spheres (GHSs). In this material, abundant ingenious internal interfaces between the crystalline graphene and the carbon matrix are created inside the hard carbon spheres. The constructed interfaces can not only work as a pathway for the escape of volatile gas generated during sucrose pyrolysis to prevent the formation of abundant pores, which leads high packing density of 0.910 g cm-3 and low surface area of 13.3 m2  g-1 , but can also provide a conductive "highway" for ions and electrons. When used as the anode material for both LIBs and sodium-ion batteries (SIBs), the GHS shows the high gravimetric/volumetric reversible capacities, high-rate performance, and low temperature properties simultaneously, implying the great potential application in practical LIBs and SIBs.

19.
ACS Appl Mater Interfaces ; 13(48): 57092-57099, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34807559

RESUMO

Designing dense carbon materials with both high capacitance and good rate performance is crucial for future development of minimized and light-weight supercapacitors but remains challenging because sluggish ion transport inhibits the efficient utilization of the energy storage sites. Herein, we report a defective and functionalized graphene block (DFGB) prepared through ball milling using controllably reduced graphene oxide (RGO) as the precursor. Rational oxygen configuration enables good electrolyte wettability and improves ion migration kinetics, facilitating high utilization of the "self-doping" defects as active sites. Benefiting from this synergistic effect, the optimized DFGB with a high compact density of 0.92 g cm-3 shows high capacitances of 302 F g-1 and 278 F cm-3 at 1 A g-1 and good rate performance with a capacitance retention of 42% at 100 A g-1, which are among the best of the reported carbons. Moreover, the symmetric device at the commercial mass loading still shows a high energy density and remarkable cycle stability, demonstrating the importance of functionalization synergy in fully realizing the compact energy storage ability of carbon materials.

20.
Small ; 17(50): e2103926, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34651429

RESUMO

Polyhedral oligomeric silsesquioxane (POSS) is a family of organic/inorganic hybrid materials with specific molecular symmetry, and shows great potential in the structural design of nanomaterials. Here, a "bottom-up" strategy is designed to fabricate 3D interconnected Si/SiOx /C nanorings (NRs) via AlCl3 -assisted aluminothermic reduction using dodecaphenyl cage silsesquioxane (T12 -Ph) as the building block. In this process, AlCl3 acts as both a liquid medium for reduction, and significantly as the catalyst to the cross-linking of phenyl groups in T12 -Ph. The obtained Si/SiOx /C NRs exhibits uniform diameter of ≈165 nm and well distribution of C and Si elements. The unique ring-like structure of Si/SiOx /C NRs makes it have great application potential in the field of lithium ion batteries. Notably, Si/SiOx /C NRs exhibits superior high-rate capacity and good cycle stability when used as anode for LIBs. More excitingly, Si/SiOx /C NRs can deliver a high reversible capacity of 517.9 mA h g-1 at ultra-low temperature of -70 °C, and the capacity retention as high as ≈50% of that at 25 °C. This work not only broadens structural design of carbon-based nanomaterials but also provides more possibilities for the application of POSS.

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