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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Hydrothermal self-assembly and supercapacitive behaviors of Co(II) ion-modified graphene aerogels in H{sub 2}SO{sub 4} electrolyte

Highlights: • 3D Co(II) ions modified graphene aerogels were prepared by one-step hydrothermal process. • The aerogel electrodes showed hybrid supercapacitor behaviors. • The aerogel electrodes exhibited high rate capability and long-term cycling stability. - Abstract: Reduced graphene oxide (r-GO) aerogels decorated with divalent cobalt ions were synthesized via a one-pot hydrothermal self-assembly route. The interaction of Co(II) ions with 3D r-GO aerogels was investigated by spectroscopic techniques, including Raman, attenuated total reflectance infrared, and X-ray photoelectron spectroscopies. The excellent electrochemical properties of the aerogels were confirmed by cyclic voltammetry, galvanostatic charge/discharge tests, and electrochemical impedance spectroscopy in an acid electrolyte (1 M H{sub 2}SO{sub 4}). The Co(II) ion-modified r-GO aerogels can be used as high-performance hybrid supercapacitor materials with a specific capacitance of 387.2 F g{sup –1} at 1 A g{sup –1} current density and a good cycling stability without capacity decay over 1000 cycles. The mechanical integrity enhancement of the hybrid r-GO aerogel framework and the improvement in its unique capacitive performance are attributed to the efficient interconnection produced by electro-active Co(II) ions.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Fabrication of free-standing NiCo{sub 2}O{sub 4} nanoarrays via a facile modified hydrothermal synthesis method and their applications for lithium ion batteries and high-rate alkaline batteries

Graphical abstract: Hydrothermal-synthesized NiCo{sub 2}O{sub 4} nanoflake arrays exhibit porous structure and high capacity as well as good cycling life for lithium ion batteries and alkaline batteries. - Highlights: • Self-supported NiCo{sub 2}O{sub 4} nanoflake arrays are prepared by a hydrothermal method. • NiCo{sub 2}O{sub 4} nanoflake arrays show high capacity and good cycling life. • Porous nanoflake arrays structure is favorable for fast ion/electron transfer. - Abstract: Self-supported NiCo{sub 2}O{sub 4} nanoflake arrays on nickel foam are prepared by a facile hydrothermal method. The obtained NiCo{sub 2}O{sub 4} nanoflakes with thicknesses of ∼25 nm grow vertically to the nickel foam substrate and form an interconnected porous network with pore diameters of 50–500 nm. As anode material of LIBs, the NiCo{sub 2}O{sub 4} nanoflake arrays show a high initial coulombic efficiency of 76%, as well as good cycling stability with a capacity of 880 mAh g{sup −1} at 0.5 A g{sup −1}, and 523 mAh g{sup −1} at 1.5 A g{sup −1} after 50 cycles. As the cathode of alkaline batteries, a high capacity of 95 mAh g{sup −1} is achieved at 2 A g{sup −1} and 94% retention is maintained after 10,000 cycles. The superior electrochemical performance is mainly due to the unique nanoflake arrays structure with large surface area and shorter diffusion length for mass and charge transport.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Tollen’s reagent assisted synthesis of hollow polyaniline microsphere/Ag nanocomposite and its applications in sugar sensing and electromagnetic shielding

Graphical abstract: Probable scheme to demonstrate the mechanism of PnHMAg showing enhanced EMI shielding compared to PnHM. - Highlights: • Hollow polyaniline microsphere (PnHM) exhibits superior properties due to its enhanced surface to volume ratio. • PnHMAg has been used in developing efficient sensor for the detection of sugar. • Presence of Ag nanoparticles enhances the electrical conductivity of PnHMAg resulting in the improvement of electromagnetic interference shielding in both X- and S-band regions. • Such properties could be harnessed effectively for development of devices for commercial as well as national purposes. - Abstract: The present study is focused on synthesis of polyaniline hollow microspheres (PnHM) nanocomposites of silver (Ag) i.e., PnHMAg by emulsion polymerization of aniline and Tollen’s reagent as a source for Ag nanoparticles. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis of PnHMAg indicated presence of silver nanoparticles dispersed on polyaniline surface. The electrical conductivity of PnHMAg is increased by ∼6 times compared to PnHM. Cyclic voltammogram of PnHM in sugar sensing exhibits characteristics redox peaks at ∼0.09 (sugar) and ∼0.53 V (polyaniline). Interestingly, PnHMAg showed a single peak at ∼−0.18 V with increased intensity (∼5 times) indicating its high sugar sensing ability. PnHMAg also exhibits high shielding efficiency of 19.5 dB (11.2 GHz) due to the presence of highly conducting Ag nanoparticles. TEM studies confirmed that Ag nanoparticles are well distributed on PnHM. As a result, a continuous electronic path is developed due to enhanced interconnectivity of PnHM.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Construction of hierarchical porous NiCo{sub 2}O{sub 4} films composed of nanowalls as cathode materials for high-performance supercapacitor

Graphical abstract: Hydrothermal-synthesized NiCo{sub 2}O{sub 4} mesowall films exhibit porous structure and high capacity as well as good cycling life for supercapacitor application. - Highlights: • Hierarchical porous NiCo{sub 2}O{sub 4} nanowall films are prepared by a hydrothermal method. • NiCo{sub 2}O{sub 4} nanowall films show excellent electrochemical performance. • Hierarchical porous film structure is favorable for fast ion/electron transfer. - Abstract: Hierarchical porous NiCo{sub 2}O{sub 4} films composed of nanowalls on nickel foam are synthesized via a facile hydrothermal method. Besides the mesoporous walls, the NiCo{sub 2}O{sub 4} nanowalls are interconnected with each other to form hierarchical porous structure. These unique porous structured films possess a high specific surface area. The supercapacitor performance of the hierarchical porous NiCo{sub 2}O{sub 4} film is fully characterized. A high capacity of 130 mA h g{sup −1} is achieved at 2 A g{sup −1} with 97% capacity maintained after 2,000 cycles. Importantly, 75.6% of capacity is retained when the current density changes from 3 A g{sup −1} to 36 A g{sup −1}. The superior electrochemical performance is mainly due to the unique hierarchical porous structure with large surface area as well as shorter diffusion length for ion and charge transport.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Synthesis, characterization and rate capability performance of the micro-porous MnO{sub 2} nanowires as cathode material in lithium batteries

Graphical abstract: Translating MnO{sub 2} nanowires as cathode materials in coin cell and studying their discharge behavior and cycling stability at different C-rates. - Highlights: • MnO{sub 2} nanowires have been synthesized via hydrothermal route. • The nanowires were employed as cathode materials in Li-batteries. • Discharge and cycling stability were studied at different C-rates. • Specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1} were attained. - Abstract: A peculiar architecture of one-dimensional MnO{sub 2} nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 10{sup 2}. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g{sup −1} and 200 W kg{sup −1}, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2015

Synthesis of nickel oxide nanospheres by a facile spray drying method and their application as anode materials for lithium ion batteries

Graphical abstract: NiO nanospheres prepared by a facile spray drying method show high lithium ion storage performance as anode of lithium ion battery. - Highlights: • NiO nanospheres are prepared by a spray drying method. • NiO nanospheres are composed of interconnected nanoparticles. • NiO nanospheres show good lithium ion storage properties. - Abstract: Fabrication of advanced anode materials is indispensable for construction of high-performance lithium ion batteries. In this work, nickel oxide (NiO) nanospheres are fabricated by a facial one-step spray drying method. The as-prepared NiO nanospheres show diameters ranging from 100 to 600 nm and are composed of nanoparticles of 30–50 nm. As an anode for lithium ion batteries, the electrochemical properties of the NiO nanospheres are investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge tests. The specific reversible capacity of NiO nanospheres is 656 mA h g{sup −1} at 0.1 C, and 476 mA h g{sup −1} at 1 C. The improvement of electrochemical properties is attributed to nanosphere structure with large surface area and short ion/electron transfer path.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2016

Self-supported porous CoO semisphere arrays as binder-free electrodes for high-performance lithium ion batteries

Highlights: • CoO semisphere arrays are prepared by a template-assisted electrodeposition method. • Interconnected semisphere arrays are favorable for fast ion/electron transfer. • CoO semisphere arrays show excellent Li ion storage performance. - Abstract: Construction of hierarchical porous metal oxides arrays is critical for the development of high-performance electrochemical energy storage devices. Herein we report porous CoO semisphere arrays using an electrodeposited polystyrene template method. Interestingly, the as-prepared porous CoO semisphere arrays consist of bowl-like semispheres with diameters of ∼500 nm and show highly porous structure. As a preliminary test as anode for lithium ion batteries (LIBs), the porous CoO semispheres arrays exhibit superior electrochemical performances with good cyclability (695.5 mAh g{sup −1} after 150 cycles at 0.5 A g{sup −1}) and high-rate capability. The porous semispherical architecture provides positive roles in the enhancement of electrochemical properties, including fast electronic transportation path, short diffusion of Li ion and high sufficient interfacial contact area between the active material and the electrolyte. The developed methodology enables a new fabrication of porous metal oxides with applications in electro-catalysis, optical and electrochemical devices.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Controllable synthesis of cobalt oxide nanoflakes on three-dimensional porous cobalt networks as high-performance cathode for alkaline hybrid batteries

Highlights: • Construct self-supported porous Co networks. • Porous Co/CoO composite films show high capacity and good cycling life. • Porous conductive metal network is favorable for fast ion/electron transfer. - Abstract: Herein we report porous three-dimensional cobalt networks supported CoO nanoflakes by the combination of successive electro-deposition methods. The electrodeposited Co networks have average large pores of ∼5 μm and all the branches are composed of interconnected nanoparticles. CoO nanoflakes with thickness of ∼15 nm are uniformly coated on the Co networks forming self-supported Co/CoO composite films. The as-prepared Co/CoO composite films possess combined properties of porous structure and strong mechanical stability. As cathode for alkaline hybrid batteries, the Co/CoO composite films exhibit good electrochemical performances with high capacity of 83.5 mAh g{sup −1} at 1 A g{sup −1} and stable high-rate cycling life (65 mAh g{sup −1} at 10 A g{sup −1} after 15,000 cycles). The hierarchical porous architecture provides positive roles in the enhancement of electrochemical properties, including fast electronic transportation path, short diffusion of ions and high contact area between the active material and the electrolyte.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Preparation of mesoporous titanium dioxide anode by a film- and pore-forming agent for the dye-sensitized solar cell

Highlights: • PVP is used as a film- and pore-forming agent to prepare the mesoporous TiO{sub 2} anode. • The TiO{sub 2} anode supplies high surface area for the dye adsorption. • The DSSC efficiency is strongly dependent on the pore properties of the TiO{sub 2} anode. • The DSSC efficiency with the TiO{sub 2} anode prepared by 20 wt% PVP reaches 8.39%. - Abstract: A novel mean of generating mesoporous titanium dioxide (TiO{sub 2}) anodes by employing polyvinylpyrrolidone (PVP) as the film- and pore-forming agent are proposed for dye-sensitized solar cells (DSSCs). The influences on the morphology and photovoltaic performances of the TiO{sub 2} anodes are investigated by adjusting the PVP content in synthesizing the mesoporous TiO{sub 2} anodes. The photovoltaic conversion efficiency of the DSSC is found to be strongly dependent on the pore properties of the TiO{sub 2} anode. After the sintering process, the removal of the PVP leaves porously interconnected channel structures inside the TiO{sub 2} anode, supplying enhanced specific surface area for the dye adsorption as well as the efficient electron transmission. As a result, the TiO{sub 2} anode prepared by 20 wt% PVP presents the highest performances, based on which the DSSC achieves the highest conversion efficiency of 8.39%, approximately increased by 56.53% than that of the DSSC fabricated without PVP (5.36%).

36 MATERIALS SCIENCE↗
DOE OSTI2016

Ceria nanoparticles uniformly decorated on graphene nanosheets with coral-like morphology for high-performance supercapacitors

Graphical abstract: The study reported the synthesis of coral-like CeO{sub 2}/GNs for supercapacitors. The unique architecture with overall connected framework and good conducting network of the graphene greatly boosts the Faradaic redox reaction. Therefore, the CeO{sub 2}/GNs delivers an excellent electrochemical performance. - Highlights: • The study reported the synthesis of CeO{sub 2}/GNs. • The graphene was woven into CeO{sub 2}, acting as a good conducting network. • The CeO{sub 2}/GNs shows a coral-like structure. • The architecture creates an overall connected framework. • The CeO{sub 2}/GNs delivers good capacitive performances. - Abstract: CeO{sub 2}/graphene was synthesized by a simple microwave method along with subsequent calcination. CeO{sub 2} nanoparticles with an average size of 68.8 nm are uniformly decorated on graphene nanosheets (CeO{sub 2}/GNs). The CeO{sub 2}/GNs displays a like-coral morphology. The architecture including overall connected framework, abundant intercrossed and interconnected nanochannels and perfect conducting network of the graphene, endows the CeO{sub 2}/GNs material with a superior electron and mass transport. As a result, the CeO{sub 2}/GNs gives a high specific capacitance of 503.4 F/g at 2 A/g and good cycle performance with 91.8% capacitance retention after 3000 cycles. Further, an asymmetric supercapacitors was assembled by using CeO{sub 2}/GNs as the positive electrode and activated carbon as the negative electrode, the asymmetric device demonstrate a favorable energy density of 30.2 Wh/kg at the power density of 750.0 W/kg and superior cycle life with 86.4% the capacitance retenion at 5 A/g after 3000 cycles.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Microstructures and martensitic transformation behavior of superelastic Ti-Ni-Ag scaffolds

Highlights: • The B2-R-B19′ transformation occurred in 49Ti-50.3Ni-0.7Ag alloy fibers. • Annealing treated alloy fibers showed superelastic recovery ratio of 93%. • Ageing treated scaffold had an elastic modulus of 0.67 GPa. • Ageing treated scaffold exhibited good superelasticity at human body temperature. - Abstract: Ti-Ni-Ag scaffolds were prepared by sintering rapidly solidified alloy fibers. Microstructures and transformation behaviors of alloy fibers and scaffolds were investigated by means of electron probe micro-analyzer (EPMA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The B2-R-B19′ transformation occurs in alloy fibers. The alloy fibers have good superelasticity with superelastic recovery ratio of 93% after annealing heat treatment. The as-sintered Ti-Ni-Ag scaffolds possess three-dimensional and interconnected pores and have the porosity level of 80%. The heat treated Ti-Ni-Ag scaffolds not only have an elastic modulus of 0.67 GPa, which match well with that of cancellous bone, but also show excellent superelasticity at human body temperature. In terms of the mechanical properties, the Ti-Ni-Ag scaffolds in this study can meet the main requirements of bone scaffold for the purpose of bone replacement applications.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Rational fabrication of nickel hydroxide shell on TiO{sub 2} nanorod core forming enhanced arrays for energy storage

Highlights: • Construct TiO{sub 2}/Ni(OH){sub 2} core/shell arrays by ALD-assisted HS method. • Ni(OH){sub 2} nanoflake shells show high energy storage. • Porous core/shell structure is favorable for fast ion/electron transfer. - Abstract: Integration of different functional materials into core/shell composite arrays is of great importance for high-performance energy storage. In this work, we controllably synthesize Ni(OH){sub 2} nanoflake shell on the single-crystalline TiO{sub 2} nanorod cores forming composite core/shell arrays (CSAs). Interconnected Ni(OH){sub 2} nanoflakes of 20–30 nm are uniformly coated on the TiO{sub 2} nanorods of 80–120 nm via atomic layer deposition assisted hydrothermal method. Furthermore, porous network with numerous nanopores and large surface area is formed in this core/shell structure. In view of this advantageous architecture, the designed Ni(OH){sub 2}/TiO{sub 2} CSAs are studied as cathode of alkaline batteries and show high energy storage performance with a capacity of 121 mAh g{sup −1} at 1 A g{sup −1} and 91 mAh g{sup −1} at 5 A g{sup −1}, respectively. The boosted electrochemical properties are owing to the porous core/shell architecture with improved active area and accelerated ion/electron transfer characteristics.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Gamma ray irradiation-induced variations in structure and optical properties of cerium/titanium-doped oxyfluoride transparent glass-ceramics

Highlights: • CeO{sub 2} favors CaF{sub 2} crystallization while TiO{sub 2} suppresses CaF{sub 2} crystallization. • Doping TiO{sub 2} helps reduce intrinsic coloring caused by CeO{sub 2}. • Doping CeO{sub 2} and/or TiO{sub 2} improves defects saturation over irradiation does. • Doping CeO{sub 2} allows lower radiation induced absorption coefficient than co-doping CeO{sub 2}/TiO{sub 2}. - Abstract: CeO{sub 2}/TiO{sub 2}-doped oxyfluoride transparent glass ceramics with a composition of 45SiO{sub 2}–20Al{sub 2}O{sub 3}–10CaO–25CaF{sub 2} were synthesized and irradiated by gamma ray. The effects of CeO{sub 2}/TiO{sub 2} on the structure and optical properties of the samples before and after irradiation were investigated. Doping with CeO{sub 2} causes network depolymerization and conversion of [AlO{sub 6}] to [AlO{sub 4}], enlarging the percolation region and promoting CaF{sub 2} crystallization. Co-doping with CeO{sub 2}/TiO{sub 2} helps reduce the intrinsic coloring of transparent glass ceramics containing only CeO{sub 2}, and the addition of TiO{sub 2} enhances network interconnectivity, suppressing CaF{sub 2} crystallization. Doping with CeO{sub 2} and/or TiO{sub 2} improves the structural stability of transparent glass ceramics upon irradiation and maintains the optical band gap and Urbach energy constant due to the defect saturation over the irradiation dose. Doping solely with CeO{sub 2} allows for a lower radiation-induced absorption coefficient than co-doping CeO{sub 2}/TiO{sub 2} because of the enhanced crystallization induced by CeO{sub 2} and balanceable light absorption of polyvalent cerium ions.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Biomass-derived carbon/silicon three-dimensional hierarchical nanostructure as anode material for lithium ion batteries

Highlights: • The 3D conductive framework is fabricated from biomass-derived carbon. • The enhanced performance is attributed to in-suit coating and 3D skeleton of carbon. • The synthetic strategy is low-cost and environment friendly. - Abstract: Three-dimensional hierarchical silicon/carbon nanostructure (3D AC-Si) is applied as the anode material for lithium-ion batteries (LIBs), where encapsulated Si NPs are uniformly bonded over interconnected carbon framework. The unique structure benefits from the binary functions of the naturally conductive network of biomass carbon and the in-suit carbon coating of dopamine. This 3D AC-Si composite behaves high specific capacity and good cycling stability (3353 mAh g{sup −1} at a current density of 0.2 A g{sup −1}), as well as enhanced rate capability. Our findings exhibit a new strategy for preparing low-cost and environment friendly silicon/carbon composite and has potential to be extended to other anode materials for high-performance LIBs.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Hierarchical NiCo{sub 2}O{sub 4} nanowalls composed of ultrathin nanosheets as electrode materials for supercapacitor and Li ion battery applications

Highlights: • NiCo{sub 2}O{sub 4} nanowalls composed of ultrathin nanosheets are synthesized by solvothermal reaction. • The prepared NiCo{sub 2}O{sub 4} structures possess excellent electrochemical properies. • The hierarchica electrode materials might potential applications for energy storage devices. - Abstract: In this work, NiCo{sub 2}O{sub 4} nanowalls composed of ultrathin nanosheets are fabricated successfully on Ni foam by a facile one-pot solvothermal method followed by thermolysis of the precursors. The as-prepared NiCo{sub 2}O{sub 4} products are evaluated as electrode materials for supercapacitors and lithium ion batteries. The results show high discharge capacitance of 925 mF/cm{sup 2} at a current density of 5 mA/cm{sup 2}, with remarkable cycling stability (about 24.2% loss after 6000 cycles) and excellent rate performance (71.5% capacitance retention with current density range from 1 mA/cm{sup 2} to 20 mA/cm{sup 2}). In addition, Ni foam supported NiCo{sub 2}O{sub 4} nanowalls possess excellent discharge capacity of 1100 mAh/g as lithium ion battery anode at a current density of 100 mA/g. The excellent electrochemical performance of NiCo{sub 2}O{sub 4} nanowalls could be ascribed to the unique spatial structure composed of interconnected ultrathin nanosheets, which facilitates ion penetration and electron transportation, demonstrating their potential applications as electrode materials for high performance supercapacitors and lithium ion batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Integrated carbon cloth supported LiFePO4/N-C films as high-performance cathode for lithium ion batteries

Highlights: • Construct carbon cloth supported LiFePO{sub 4}/N-C films via hydrothermal. • The LiFePO{sub 4}/N-C films show high capacity and good cycles. • Carbon cloth and N-C layer work together to provide fast ion/electron transfer. - Abstract: Fabricating advanced cathode is critical for the development of high-performance lithium ion batteries (LIBs). In this work, we develop a facile hydrothermal method for construction of LiFePO{sub 4}/N-C films on the carbon cloth forming integrated binder-free cathode. The LiFePO{sub 4}/N-C films are composed of interconnected nanoscale LiFePO{sub 4}/N-C particles with diameters of 100–200 nm. High porosity and good adhesion are obtained in the carbon cloth supported LiFePO{sub 4}/N-C films (CC + LiFePO{sub 4}/N-C films). As compared to the LiFePO{sub 4}/C powder nanoparticles, the CC + LiFePO{sub 4}/N-C films show much better electrochemical properties with higher capacities, smaller polarization and better high-rate cycling life. A high capacity of 169 mAh g{sup −1} at 1C is achieved for the carbon cloth supported LiFePO{sub 4}/N-C films, superior to the LiFePO{sub 4}/C powder nanoparticles (154 mAh g{sup −1} at 5C). This enhancement is owing to the unique integrated porous architecture and N-C coating. Our work shows a new way to construct integrated cathode for application in LIBs.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Synthesis of porous MnO2-CoO microsheets and nanocones as a high-performance battery-type capacitive material

Highlights: • Porous MnO{sub 2}-CoO microsheets and nanocones (MCMSNCs) are synthesized. • Sodium dodecyl sulfate controls the formation of specific metal oxide structures. • MCMSNCs deliver excellent capacitive performance as a battery-type material. - Abstract: A facile method via sodium dodecyl sulfate (SDS)-templated oil-bath followed by annealing treatment is reported to synthesize porous MnO{sub 2}-CoO microsheets and nanocones (MCMSNCs). Herein, surfactant SDS is firstly used to obtain Mn/Co hydroxide ultrathin microsheets and nanocones precursor, which is then transformed into interconnected porous MCMSNCs after heat treatment. As a battery-type capacitive electrode micro/nanomaterial, MCMSNCs exhibit an original specific capacity (148 C g{sup −1}) at a current density of 1 A g{sup −1} by chronopotentiometry. Moreover, MCMSNCs deliver good rate performance with 77% capacity retention from 1 to 16 A g{sup −1} and excellent cycle life with 20% loss of the maximum value as well as 118% retention of the initial one after 3000 cycles. The excellent capacitive performance of porous MCMSNCs endows it potential use as an anode electrode material in the application of electrochemical capacitors.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Graphene foam supported LiFePO4 nanosheets composite as advanced cathode for lithium ion batteries

Highlights: • Construct self-supported porous LiFePO{sub 4}/GF composite film. • Porous LiFePO{sub 4}/GF composite film show superior cycling life. • Hierarchical porous nanosheets structure boost fast electron/ion transfer. - Abstract: Smart design of advanced cathode plays a significantly important role for the development of high-performance lithium ion batteries (LIBs). In this work, we synthesized a new kind of LiFePO{sub 4}/Graphene foam (LFP/GF) integrated binder-free cathode via chemical vapor deposition (CVD) + hydrothermal method. The LFP is composed of interconnected LiFePO{sub 4} nanosheets with numerous nanopores of 50–500 nm. High porosity and good adhesion endow LiFePO{sub 4}/GF film superior electrochemical properties with remarkable high-rate capacities, small polarization and stable cycling life. A high-rate capacity of 110 mAh g{sup −1} at 24 C is obtained for the LiFePO{sub 4}/GF composite. Moreover, a high capacity retention of 95% is acquired after 160 cycles. This enhancement is due to the unique integrated porous LiFePO{sub 4} nanosheets and good support of graphene foam providing fast ion/electron transfer. Our work displays a new insight in constructing integrated cathode for application in high-performance LIBs.

77 NANOSCIENCE AND NANOTECHNOLOGY↗