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1.
Small ; 20(16): e2307579, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38044290

RESUMEN

The design and fabrication of novel carbon hosts with high conductivity, accelerated electrochemical catalytic activities, and superior physical/chemical confinement on sulfur and its reaction intermediates polysulfides are essential for the construction of high-performance C/S cathodes for lithium-sulfur batteries (LSBs). In this work, a novel biofermentation coupled gel composite assembly technology is developed to prepare cross-linked carbon composite hosts consisting of conductive Rhizopus hyphae carbon fiber (RHCF) skeleton and lamellar sodium alginate carbon (SAC) uniformly implanted with polarized nanoparticles (V2O3, Ag, Co, etc.) with diameters of several nanometers. Impressively, the RHCF/SAC/V2O3 composites exhibit enhanced physical/chemical adsorption of polysulfides due to the synergistic effect between hierarchical pore structures, heteroatoms (N, P) doping, and polar V2O3 generation. Additionally, the catalytic conversion kinetics of cathodes are effectively improved by regulating the 3D carbon structure and optimizing the V2O3 catalyst. Consequently, the LSBs assembled with RHCF/SAC/V2O3-S cathode show exceptional cycle stability (capacity retention rate of 94.0% after 200 cycles at 0.1 C) and excellent rate performance (specific capacity of 578 mA h g-1 at 5 C). This work opens a new door for the fabrication of hyphae carbon composites via fermentation for electrochemical energy storage.

2.
Small ; 20(15): e2306381, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38013253

RESUMEN

All-solid-state lithium metal batteries (LMBs) are regarded as one of the most viable energy storage devices and their comprehensive properties are mainly controlled by solid electrolytes and interface compatibility. This work proposes an advanced poly(vinylidene fluoride-hexafluoropropylene) based gel polymer electrolyte (AP-GPEs) via functional superposition strategy, which involves incorporating butyl acrylate and polyethylene glycol diacrylate as elastic optimization framework, triethyl phosphate and fluoroethylene carbonate as flameproof liquid plasticizers, and Li7La3Zr2O12 nanowires (LLZO-w) as ion-conductive fillers, endowing the designed AP-GPEs/LLZO-w membrane with high mechanical strength, excellent flexibility, low flammability, low activation energy (0.137 eV), and improved ionic conductivity (0.42 × 10-3 S cm-1 at 20 °C) due to continuous ionic transport pathways. Additionally, the AP-GPEs/LLZO-w membrane shows good safety and chemical/electrochemical compatibility with the lithium anode, owing to the synergistic effect of LLZO-w filler, flexible frameworks, and flame retardants. Consequently, the LiFePO4/Li batteries assembled with AP-GPEs/LLZO-w electrolyte exhibit enhanced cycling performance (87.3% capacity retention after 600 cycles at 1 C) and notable high-rate capacity (93.3 mAh g-1 at 5 C). This work proposes a novel functional superposition strategy for the synthesis of high-performance comprehensive GPEs for LMBs.

3.
Small ; : e2402862, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38888118

RESUMEN

Lithium-sulfur (Li-S) batteries are expected to be the next-generation energy storage system due to the ultrahigh theoretical energy density and low cost. However, the notorious shuttle effect of higher-order polysulfides and the uncontrollable lithium dendrite growth are the two biggest challenges for commercially viable Li-S batteries. Herein, these two main challenges are solved by in situ polymerization of bi-functional gel polymer electrolyte (GPE). The initiator (SiCl4) not only drives the polymerization of 1,3-dioxolane (DOL) but also induces the construction of a hybrid solid electrolyte interphase (SEI) with inorganic-rich compositions on the Li anode. In addition, diatomaceous earth (DE) is added and anchored in the GPE to obtain PDOL-SiCl4-DE electrolyte through in situ polymerization. Combined with density functional theory (DFT) calculations, the hybrid SEI provides abundant adsorption sites for the deposition of Li+, inhibiting the growth of lithium dendrites. Meanwhile, the shuttle effect is greatly alleviated due to the strong adsorption capacity of DE toward lithium polysulfides. Therefore, the Li/Li symmetric cell and Li-S full cell assembled with PDOL-SiCl4-DE exhibit excellent cycling stability. This study offers a valuable reference for the development of high performance and safe Li-S batteries.

4.
Small ; : e2401491, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38751305

RESUMEN

The design and fabrication of a lithiophilic skeleton are highly important for constructing advanced Li metal anodes. In this work, a new lithiophilic skeleton is reported by planting metal sulfides (e.g., Ni3S2) on vertical graphene (VG) via a facile ultrafast Joule heating (UJH) method, which facilitates the homogeneous distribution of lithiophilic sites on carbon cloth (CC) supported VG substrate with firm bonding. Ni3S2 nanoparticles are homogeneously anchored on the optimized skeleton as CC/VG@Ni3S2, which ensures high conductivity and uniform deposition of Li metal with non-dendrites. By means of systematic electrochemical characterizations, the symmetric cells coupled with CC/VG@Ni3S2 deliver a steady long-term cycle within 14 mV overpotential for 1800 h (900 cycles) at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the designed CC/VG@Ni3S2-Li||LFP full cell shows notable electrochemical performance with a capacity retention of 92.44% at 0.5 C after 500 cycles and exceptional rate performance. This novel synthesis strategy for metal sulfides on hierarchical carbon-based materials sheds new light on the development of high-performance lithium metal batteries (LMBs).

5.
Chemistry ; 30(19): e202304168, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38264940

RESUMEN

"Carbon Peak and Carbon Neutrality" is an important strategic goal for the sustainable development of human society. Typically, a key means to achieve these goals is through electrochemical energy storage technologies and materials. In this context, the rational synthesis and modification of battery materials through new technologies play critical roles. Plasma technology, based on the principles of free radical chemistry, is considered a promising alternative for the construction of advanced battery materials due to its inherent advantages such as superior versatility, high reactivity, excellent conformal properties, low consumption and environmental friendliness. In this perspective paper, we discuss the working principle of plasma and its applied research on battery materials based on plasma conversion, deposition, etching, doping, etc. Furthermore, the new application directions of multiphase plasma associated with solid, liquid and gas sources are proposed and their application examples for batteries (e. g. lithium-ion batteries, lithium-sulfur batteries, zinc-air batteries) are given. Finally, the current challenges and future development trends of plasma technology are briefly summarized to provide guidance for the next generation of energy technologies.

6.
Small ; 19(42): e2303210, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37330662

RESUMEN

The use of poly(1,3-dioxolane) (PDOL) electrolyte for lithium batteries has gained attention due to its high ionic conductivity, low cost, and potential for large-scale applications. However, its compatibility with Li metal needs improvement to build a stable solid electrolyte interface (SEI) toward metallic Li anode for practical lithium batteries. To address this concern, this study utilized a simple InCl3 -driven strategy for polymerizing DOL and building a stable LiF/LiCl/LiIn hybrid SEI, confirmed through X-ray photoelectron spectroscopy (XPS) and cryogenic-transmission electron microscopy (Cryo-TEM). Furthermore, density functional theory (DFT) calculations and finite element simulation (FES) verify that the hybrid SEI exhibits not only excellent electron insulating properties but also fast transport properties of Li+ . Moreover, the interfacial electric field shows an even potential distribution and larger Li+ flux, resulting in uniform dendrite-free Li deposition. The use of the LiF/LiCl/LiIn hybrid SEI in Li/Li symmetric batteries shows steady cycling for 2000 h, without experiencing a short circuit. The hybrid SEI also provided excellent rate performance and outstanding cycling stability in LiFePO4 /Li batteries, with a high specific capacity of 123.5 mAh g-1 at 10 C rate. This study contributes to the design of high-performance solid lithium metal batteries utilizing PDOL electrolytes.

7.
Small ; 19(24): e2300494, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36920095

RESUMEN

Lithium-rich layered oxide (LRLO) materials have attracted significant attention due to their high specific capacity, low cost, and environmental friendliness. However, owing to its unique capacity activation mechanism, the release of lattice oxygen during the first charge process leads to a series of problems, such as severe voltage decay, poor cycle stability, and poor rate performance. Herein, a fluorinated quasi-solid-state electrolyte (QSSE) via a simple thermal polymerization method toward lithium metal batteries with LRLO materials is reported. The well-designed QSSE exhibits an ionic conductivity of 6.4 × 10-4 S cm-1 at 30 °C and a wide electrochemical stable window up to 5.6 V. Most importantly, XPS spectra demonstrate the generation of a LiF-rich electrode-electrolyte interface (EEI), where the in situ generated LiF provides strong protection against the structural degradation of LRLO materials and directs the uniform plating/stripping behaviors of lithium-ions to inhibit the formation of lithium dendrites. As a result, LRLO/QSSE/Li batteries exhibit excellent rate performance and demonstrate a large initial capacity for 209.7 mA h g-1 with a capacity retention of 80.8% after 200 cycles at 0.5C. This work provides a new insight for the LiF-rich EEI design of safe, high-performance quasi-solid-state lithium metal batteries.

8.
Small ; 19(24): e2208164, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36916700

RESUMEN

Solid-state lithium-sulfur batteries (SSLSBs) have attracted tremendous research interest due to their large theoretical energy density and high safety, which are highly important indicators for the development of next-generation energy storage devices. Particularly, safety and "shuttle effect" issues originating from volatile and flammable liquid organic electrolytes can be fully mitigated by switching to a solid-state configuration. However, their road to thecommercial application is still plagued with numerous challenges, most notably the intrinsic electrochemical instability of solid-state electrolytes (SSEs) materials and their interfacial compatibility with electrodes and electrolytes. In this review, a critical discussion on the key issues and problems of different types of SSEs as well as the corresponding optimization strategies are first highlighted. Then, the state-of-the-art preparation methods and properties of different kinds of SSE materials, and their manufacture, characterization and performance in SSLSBs are summarized in detail. Finally, a scientific outlook for the future development of SSEs and the avenue to commercial application of SSLSBs is also proposed.

9.
Neurosurg Rev ; 46(1): 118, 2023 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-37166553

RESUMEN

The novel robot-assisted (RA) technique has been utilized increasingly to improve the accuracy of cervical pedicle screw placement. Although the clinical application of the RA technique has been investigated in several case series and comparative studies, the superiority and safety of RA over conventional freehand (FH) methods remain controversial. Meanwhile, the intra-pedicular accuracy of the two methods has not been compared for patients with cervical traumatic conditions. This study aimed to compare the rate and risk factors of intra-pedicular accuracy of RA versus the conventional FH approach for posterior pedicle screw placement in cervical traumatic diseases. A total of 52 patients with cervical traumatic diseases who received cervical screw placement using RA (26 patients) and FH (26 patients) techniques were retrospectively included. The primary outcome was the intra-pedicular accuracy of cervical pedicle screw placement according to the Gertzbin-Robbins scale. Secondary outcome parameters included surgical time, intraoperative blood loss, postoperative drainage, postoperative hospital stay, and complications. Moreover, the risk factors that possibly affected intra-pedicular accuracy were assessed using univariate analyses. Out of 52 screws inserted using the RA method, 43 screws (82.7%) were classified as grade A, with the remaining 7 (13.5%) and 2 (3.8%) screws classified as grades B and C. In the FH cohort, 60.8% of the 79 screws were graded A, with the remaining screws graded B (21, 26.6%), C (8, 10.1%), and D (2, 2.5%). The RA technique showed a significantly higher rate of optimal intra-pedicular accuracy than the FH method (P = 0.008), but there was no significant difference between the two groups in terms of clinically acceptable accuracy (P = 0.161). Besides, the RA technique showed remarkably longer surgery time, less postoperative drainage, shorter postoperative hospital stay, and equivalent intraoperative blood loss and complications than the FH technique. Furthermore, the univariate analyses showed that severe obliquity of the lateral atlantoaxial joint in the coronal plane (P = 0.003) and shorter width of the lateral mass at the inferior margin of the posterior arch (P = 0.014) were risk factors related to the inaccuracy of C1 screw placement. The diagnosis of HRVA (P < 0.001), severe obliquity of the lateral atlantoaxial joint in the coronal plane (P < 0.001), short pedicle width (P < 0.001), and short pedicle height (P < 0.001) were risk factors related to the inaccuracy of C2 screw placement. RA cervical pedicle screw placement was associated with a higher rate of optimal intra-pedicular accuracy to the FH technique for patients with cervical traumatic conditions. The severe obliquity of the lateral atlantoaxial joint in the coronal plane independently contributed to high rates of the inaccuracy of C1 and C2 screw placements. RA pedicle screw placement is safe and useful for cervical traumatic surgery.


Asunto(s)
Articulación Atlantoaxoidea , Tornillos Pediculares , Robótica , Fusión Vertebral , Humanos , Tornillos Pediculares/efectos adversos , Estudios Retrospectivos , Vértebras Cervicales/cirugía , Fusión Vertebral/métodos
10.
Nano Lett ; 22(3): 1374-1381, 2022 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-35060737

RESUMEN

The proliferation of lithium (Li) dendrites stemming from uncontrollable Li deposition seriously limits the practical application of Li metal batteries. The regulation of uniform Li deposition is thus a prerequisite for promoting a stable Li metal anode. Herein, a commercial lithiophilic skeleton of soybean protein fiber (SPF) is introduced to homogenize the Li-ion flux and induce the biomimetic Li growth behavior. Especially, the SPF can promote the formation of a LiF-nanocrystal-enriched interface upon cycling, resulting in low interfacial impedance and rapid charge transfer kinetics. Finally, the SPF-mediated Li metal anode can achieve high Coulombic efficiency of 98.7% more than 550 cycles and a long-term lifespan over 3400 h (∼8500 cycles) in symmetric tests. Furthermore, the practical pouch cell modified with SPF can maintain superior electrochemical performance over 170 cycles under a low N/P ratio and high mass loading of the cathode.


Asunto(s)
Suministros de Energía Eléctrica , Litio , Nanopartículas , Proteínas de Soja , Electrodos , Litio/química , Proteínas de Soja/química
11.
Small ; 17(37): e2101326, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34331396

RESUMEN

Argyrodite Li6 PS5 Cl with high Li+ conductivity is a promising material for solid-state electrolytes (SSEs) in all-solid-state lithium batteries (ASSLBs). However, the narrow electrochemical window of Li6 PS5 Cl limits its applications in ASSLBs with high energy densities, and those that consist of high-voltage cathode materials and metallic lithium anodes. Unstable lithium deposition and stripping at interfaces is also a factor that restricts its industrialization. Herein, the authors investigated the electrochemical stability of Li6 PS5 Cl using it as both the cathode and electrolyte. The Li6 PS5 Cl-C/Li6 PS5 Cl/Li cell and symmetric Li/Li6 PS5 Cl/Li cells failed after a certain number of cycles, and subsequently healed electrochemically. This failure/healing phenomenon recurred during the cycling process. The self-healing behavior is closely related to the electrochemical window, which suggests that it can be controlled by the charge-discharge voltage range. In-depth X-ray photoelectron spectroscopy, in situ Raman spectroscopy, and in situ electrochemical impedance spectroscopy revealed the reversible Li6 PS5 Cl decomposition and metallic lithium growth inside the electrolyte during the cycling process. This self-healing behavior is mainly attributed to the reciprocating lithium growth and reversible redox reaction of the Li6 PS5 Cl decomposition. The proposed self-healing mechanism is a key aspect for sulfide-based SSEs, guiding the interface modification, and material design of ASSLBs.

12.
Environ Sci Technol ; 54(4): 2539-2547, 2020 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-31985212

RESUMEN

Development of low-cost, high-efficiency, and environmentally benign adsorbents for mercury removal is of significant importance for environmental remediation. Herein, we report a novel porous puffed rice carbon (PRC) with co-implanted metal iron and sulfur, forming a high-quality PRC/Fe@S composite as a high-efficiency adsorbent for mercury removal from aqueous solution. The in situ-formed Fe nanoparticles in PRC are strongly coupled with sulfur via a supercritical CO2 fluid approach and dispersed homogeneously in the cross-linked hierarchical porous architecture. The pore formation mechanism of Fe on PRC is also proposed. The optimized PRC/Fe@S composite offers superior selective affinity, high removal efficiency, and ultrahigh adsorption capacity of up to 738.0 mg g-1. It is demonstrated that the hierarchical porous carbon in the PRC/Fe@S composite not only acts as a framework to stabilize and disperse Fe nanoparticles but also provides abundant pores and voids for absorbing Hg(II) from aqueous solution. More importantly, the absorbed Hg(II) can be reduced to Hg(0) by Fe and further chemically immobilized by sulfur. The enhanced coupled effect is discussed and proposed. Therefore, an innovative adsorption mechanism of adsorption-reduction-immobilization is proposed, which offers a new prospect in developing high-efficiency carbon-based adsorbents in environmental remediation.


Asunto(s)
Mercurio , Oryza , Adsorción , Carbono , Hierro , Azufre
13.
J Sep Sci ; 43(12): 2487-2494, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32294314

RESUMEN

Callicarpa kwangtungensis Chun is a traditional Chinese medicine that has various therapeutic effects. Despite its wide use in Chinese medicine, the study is still quite limited, especially its chemical compositions. In this research, an ultra-high-pressure liquid chromatography coupled with Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry tandem mass spectrometry method was utilized to analyze its chemical compositions for the first time. As a result, a total of 124 compounds, including 20 phenylethanoid glycosides, 31 flavonoids, 36 organic acids, 26 terpenoids and 11 phenols, were identified or tentatively characterized in 30 min. Among them, 49 compounds, including 5 phenylethanoid glycosides, 12 flavonoids, 16 organic acids, 12 terpenoids, and 4 phenols, were identified in Callicarpa kwangtungensis Chun for the first time. Besides, the fragmentation pathways were also discussed. This research established a rapid and reliable method to analyze the chemical compositions of complicated herb without the process of isolation, and provide abundant information on the chemical material basis for further bioactivity and quality control studies.


Asunto(s)
Callicarpa/química , Medicamentos Herbarios Chinos/análisis , Cromatografía Líquida de Alta Presión , Espectrometría de Masas , Medicina Tradicional China , Estructura Molecular
14.
Small ; 15(38): e1902032, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31368636

RESUMEN

Increasing awareness toward environmental remediation and renewable energy has led to a vigorous demand for exploring a win-win strategy to realize the eco-efficient conversion of pollutants ("trash") into energy-storage nanomaterials ("treasure"). Inspired by the biological metabolism of bacteria, Acidithiobacillus ferrooxidans (A. ferrooxidans) is successfully exploited as a promising eco-friendly sustainable biofactory for the controllable fabrication of α-Fe2 O3 nanorods via the oxidation of soluble ferrous irons to insoluble ferric substances (Jarosite, KFe3 (SO4 )2 (OH)6 ) and a facile subsequent heat treatment. It is demonstrated that the stable solid electrolyte interphase layers and marvelous cracks in situ formed in biometabolic α-Fe2 O3 nanorods play important roles that not only significantly enhance the structure stability but also facilitate electron and ion transfer. Consequently, these biometabolic α-Fe2 O3 nanorods deliver a superior stable capacity of 673.9 mAh g-1 at 100 mA g-1 over 200 cycles and a remarkable multi-rate capability that observably prevails over the commercial counterpart. It is highly expected that such biological synthesis strategies can shed new light on an emerging field of research interconnecting biotechnology, energy technology, environmental technology, and nanotechnology.


Asunto(s)
Acidithiobacillus/química , Suministros de Energía Eléctrica , Litio/química , Nanoestructuras/química , Nanotubos/química , Nanotecnología/métodos
15.
Small ; 15(33): e1902249, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31231950

RESUMEN

The ability to efficiently convert CO2 into nanocarbons at low temperatures is highly desirable, as it would enable the environmentally benign utilization of greenhouse gases, yet this remains a considerable challenge. Herein, a one-step, ultrafast, and scalable strategy is demonstrated to efficiently convert CO2 into morphology-controlled nanocarbons at low temperatures. The conversion reactions between CO2 and LiH are achieved in less than 30 s at moderate conditions by introducing a very small amount of water, ball milling, or heating. Nanocarbons featuring wildly tunable morphology with characteristic dimensions ranging from nanoscale to macroscale are successfully synthesized by controlling the CO2 pressure and the synthesis routes. The gas blowing velocity and its distribution are revealed as the main reasons for the CO2 pressure and synthesis route dependent morphology and porosity of nanocarbons. Moreover, a two closed-loop reaction process including five-stage reactions is proposed for nanocarbons synthesis and LiH regeneration. The strategy provides a new opportunity for efficient and environmentally benign nanocarbons synthesis.

16.
Chemistry ; 25(32): 7719-7725, 2019 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-30972842

RESUMEN

Silicon oxycarbides (SiOC) are regarded as potential anode materials for lithium-ion batteries, although inferior cycling stability and rate performance greatly limit their practical applications. Herein, amorphous SiOC is synthesized from Chlorella by means of a biotemplate method based on supercritical fluid technology. On this basis, tin particles with sizes of several nanometers are introduced into the SiOC matrix through the biosorption feature of Chlorella. As lithium-ion battery anodes, SiOC and Sn@SiOC can deliver reversible capacities of 440 and 502 mAh g-1 after 300 cycles at 100 mA g-1 with great cycling stability. Furthermore, as-synthesized Sn@SiOC presents an excellent high-rate cycling capability, which exhibits a reversible capacity of 209 mAh g-1 after 800 cycles at 5000 mA g-1 ; this is 1.6 times higher than that of SiOC. Such a novel approach has significance for the preparation of high-performance SiOC-based anodes.

17.
Arch Virol ; 164(1): 195-200, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30302584

RESUMEN

Feline herpesvirus type 1 (FHV-1) is a highly contagious pathogen of domestic cats and other members of the family Felidae. Point-of-care diagnosis of persistent infection in cats is essential for control of its spread. A recombinase polymerase amplification (RPA) assay (RPA-LFD-FHV) combined with a lateral flow dipstrip (LFD) was developed that uses human body heat for incubation. Sensitivity was evaluated by testing a serial dilution of a control plasmid, and specificity was evaluated by testing related viruses. Swab samples from cats with suspected infection were tested by RPA-LFD-FHV, and the results were compared to those obtained by PCR to evaluate its clinical performance. The RPA-FLD-FHV assay was carried out successfully within 20 min, using body heat for incubation. The RPA-FLD-FHV had a detection limit of 103 copies of the FHV-1 gD gene, which was lower than that of PCR, which was 104 copies. The assay could detect templates of FHV-1 but not those of other feline and canine viruses. Viruses in boiled samples could be efficiently detected by the RPA-FLD-FHV. Thirty-one out of the 80 samples were positive by the RPA-FLD-FHV assay, whereas only 27 were positive by PCR. DNA sequencing confirmed that the four samples that were positive by RPA-FLD-FHV but negative by PCR were indeed positive. These results indicate that RPA-FLD-FHV is applicable for clinical use. The RPA-FLD-FHV assay is a simple, rapid, and reliable method for point-of-care diagnosis of FHV-1 infection.


Asunto(s)
Enfermedades de los Gatos/virología , Herpesviridae/clasificación , Herpesviridae/aislamiento & purificación , Sistemas de Atención de Punto , Animales , Enfermedades de los Gatos/diagnóstico , Gatos , Reacción en Cadena de la Polimerasa/veterinaria , Sensibilidad y Especificidad , Varicellovirus
18.
Nanotechnology ; 30(14): 144001, 2019 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-30620932

RESUMEN

A novel, flexible non-precious-metal oxygen reduction reaction catalyst is fabricated by direct pyrolysis of carbon cloth decorated with an iron-coordinated aniline and pyrrole copolymer. The resultant Fe-N/C manifests superior activity, long-term stability in alkaline media and comparable activity in acidic electrolyte. The precursor carbon cloth modified with aniline and pyrrole copolymer provides high densities of carbon, nitrogen and iron-doping sites, which generates a great many active sites. Compared to the Pt/C catalyst, Fe-N/C pyrolyzed at 850 °C (Fe-N/C-850) shows excellent activity with onset and half-wave potentials of 17 mV and -174 mV in 0.1 M KOH, which are more activated than an iron-free catalyst (-29 mV and -235 mV) and comparable to those of Pt/C (28 mV and -237 mV) with the same loading. The electrocatalysis and reaction kinetics results demonstrate that Fe-N/C-850 will be a promising catalyst at low cost for applications in fuel cells.

19.
Nano Lett ; 18(5): 3104-3112, 2018 05 09.
Artículo en Inglés | MEDLINE | ID: mdl-29692176

RESUMEN

High ionic conductivity, satisfactory mechanical properties, and wide electrochemical windows are crucial factors for composite electrolytes employed in solid-state lithium-ion batteries (SSLIBs). Based on these considerations, we fabricate Mg2B2O5 nanowire enabled poly(ethylene oxide) (PEO)-based solid-state electrolytes (SSEs). Notably, these SSEs have enhanced ionic conductivity and a large electrochemical window. The elevated ionic conductivity is attributed to the improved motion of PEO chains and the increased Li migrating pathway on the interface between Mg2B2O5 and PEO-LiTFSI. Moreover, the interaction between Mg2B2O5 and -SO2- in TFSI- anions could also benefit the improvement of conductivity. In addition, the SSEs containing Mg2B2O5 nanowires exhibit improved the mechanical properties and flame-retardant performance, which are all superior to the pristine PEO-LiTFSI electrolyte. When these multifunctional SSEs are paired with LiFePO4 cathodes and lithium metal anodes, the SSLIBs show better rate performance and higher cyclic capacity of 150, 106, and 50 mAh g-1 under 0.2 C at 50, 40, and 30 °C. This strategy of employing Mg2B2O5 nanowires provides the design guidelines of assembling multifunctional SSLIBs with high ionic conductivity, excellent mechanical properties, and flame-retardant performance at the same time.

20.
Nano Lett ; 17(5): 2967-2972, 2017 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-28388080

RESUMEN

An all solid-state lithium-ion battery with high energy density and high safety is a promising solution for a next-generation energy storage system. High interface resistance of the electrodes and poor ion conductivity of solid-state electrolytes are two main challenges for solid-state batteries, which require operation at elevated temperatures of 60-90 °C. Herein, we report the facile synthesis of Al3+/Nb5+ codoped cubic Li7La3Zr2O12 (LLZO) nanoparticles and LLZO nanoparticle-decorated porous carbon foam (LLZO@C) by the one-step Pechini sol-gel method. The LLZO nanoparticle-filled poly(ethylene oxide) electrolyte shows improved conductivity compared with filler-free samples. The sulfur composite cathode based on LLZO@C can deliver an attractive specific capacity of >900 mAh g-1 at the human body temperature 37 °C and a high capacity of 1210 and 1556 mAh g-1 at 50 and 70 °C, respectively. In addition, the solid-state Li-S batteries exhibit high Coulombic efficiency and show remarkably stable cycling performance.

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