scholarly journals Atomic-level structure engineering of metal oxides for high-rate oxygen intercalation pseudocapacitance

2018 ◽  
Vol 4 (10) ◽  
pp. eaau6261 ◽  
Author(s):  
Tao Ling ◽  
Pengfei Da ◽  
Xueli Zheng ◽  
Binghui Ge ◽  
Zhenpeng Hu ◽  
...  
Keyword(s):  
Energy Density ◽  
Electrode Materials ◽  
Level Structure ◽  
Atomic Level ◽  
Atomic Scale ◽  
High Rate ◽  
Grand Challenge ◽  
Oxide Material ◽  
Capacitive Properties ◽  
Structure Engineering

Atomic-level structure engineering can substantially change the chemical and physical properties of materials. However, the effects of structure engineering on the capacitive properties of electrode materials at the atomic scale are poorly understood. Fast transport of ions and electrons to all active sites of electrode materials remains a grand challenge. Here, we report the radical modification of the pseudocapacitive properties of an oxide material, ZnxCo1−xO, via atomic-level structure engineering, which changes its dominant charge storage mechanism from surface redox reactions to ion intercalation into bulk material. Fast ion and electron transports are simultaneously achieved in this mixed oxide, increasing its capacity almost to the theoretical limit. The resultant ZnxCo1−xO exhibits high-rate performance with capacitance up to 450 F g−1 at a scan rate of 1 V s−1, competing with the state-of-the-art transition metal carbides. A symmetric device assembled with ZnxCo1−xO achieves an energy density of 67.3 watt-hour kg−1 at a power density of 1.67 kW kg−1, which is the highest value ever reported for symmetric pseudocapacitors. Our finding suggests that the rational design of electrode materials at the atomic scale opens a new opportunity for achieving high power/energy density electrode materials for advanced energy storage devices.

Atomic-level structure engineering of Ni-substituted Ni Co3−S4 for enhancing performance of supercapacitors

2019 ◽  
Vol 851 ◽  
pp. 113474 ◽  
Author(s):  
Dandan Wu ◽  
Xuedan Song ◽  
Weiwei Qiu ◽  
Suzhen Ren ◽  
Ying Yang ◽  
...  
Keyword(s):  
Level Structure ◽  
Atomic Level ◽  
Structure Engineering

scholarly journals Self-Supported Sheets-on-Wire CuO@Ni(OH)2/Zn(OH)2 Nanoarrays for High-Performance Flexible Quasi-Solid-State Supercapacitor

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 680
Author(s):  
Jianyang Jiang ◽  
Xiong Xiong Liu ◽  
Jiayu Han ◽  
Ke Hu ◽  
Jun Song Chen
Keyword(s):  
Solid State ◽  
Energy Density ◽  
Electrode Materials ◽  
Red Light ◽  
High Capacity ◽  
High Energy ◽  
High Rate ◽  
High Energy Density ◽  
Supercapacitor Application ◽  
Charge Discharge

Transition metal hydroxides have attracted a lot of attention as the electrode materials for supercapacitors owing to their relatively high theoretical capacity, low cost, and facile preparation methods. However, their low intrinsic conductivity deteriorates their high-rate performance and cycling stability. Here, self-supported sheets-on-wire CuO@Ni(OH)2/Zn(OH)2 (CuO@NiZn) composite nanowire arrays were successfully grown on copper foam. The CuO nanowire backbone provided enhanced structural stability and a highly efficient electron-conducting pathway from the active hydroxide nanosheets to the current collector. The resulting CuO@NiZn as the battery-type electrode for supercapacitor application delivered a high capacity of 306.2 mAh g−1 at a current density of 0.8 A g−1 and a very stable capacity of 195.1 mAh g−1 at 4 A g−1 for 10,000 charge–discharge cycles. Furthermore, a quasi-solid-state hybrid supercapacitor (qss HSC) was assembled with active carbon, exhibiting 125.3 mAh g−1 at 0.8 A g−1 and a capacity of 41.6 mAh g−1 at 4 A g−1 for 5000 charge–discharge cycles. Furthermore, the qss HSC was able to deliver a high energy density of about 116.0 Wh kg−1. Even at the highest power density of 7.8 kW kg−1, an energy density of 20.5 Wh kg−1 could still be obtained. Finally, 14 red light-emitting diodes were lit up by a single qss HSC at different bending states, showing good potential for flexible energy storage applications.

scholarly journals Regulating Surface and Local Chemistry in High Na-content P2-type Cathode to Achieve Ultrahigh Power and Low Temperature Sodium Storage

2021 ◽  
Author(s):  
Qinhao Shi ◽  
Ruijuan Qi ◽  
Xiaochen Feng ◽  
Jing Wang ◽  
Yong Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electrode Materials ◽  
Rate Capability ◽  
Atomic Scale ◽  
High Rate ◽  
Layered Oxides ◽  
Electronic Band ◽  
Complete Solid Solution ◽  
Key Issues ◽  
Electronic Band Gap

Abstract Application of sodium ion batteries in grid-scale energy storage demands electrode materials that facilitate fast and stable charge storage from room-temperature to sub-zero temperature range. The key issues that hinder P2-type layered oxides from achieving such goals are their unsatisfied charge transfer kinetics and unavoidable surface fading. Herein, we report a P2-type Na0.78Ni0.31Mn0.67Nb0.02O2 whereby the trace Nb substitution simultaneously reduces the electronic band gap and ionic diffusion energy barrier, thus enables fast electron and Na+ mobility (~10-9 cm s-1 at -40 °C). While the Nb induced atomic-scale surface pre-construction efficiently prevents the electrolyte penetration and surface metal dissolution. The material demonstrates a record high rate capability (50 C), unprecedented low temperature performance and ultrahigh cycling stability (98% capacity retention at -40 °C with 76% capacity remaining after 1800 cycles). Different from literatures, this work shows that complete solid-solution is not always critical for high rate performance.

scholarly journals Signature of local stress states in the deformation behavior of metallic glasses

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Xilei Bian ◽  
Daniel Şopu ◽  
Gang Wang ◽  
Baoan Sun ◽  
Jozef Bednarčik ◽  
...  
Keyword(s):  
Shear Band ◽  
Metallic Glasses ◽  
Level Structure ◽  
Local Stress ◽  
Atomic Level ◽  
Range Order ◽  
Atomic Scale ◽  
Activation Process ◽  
Eshelby Inclusion ◽  
Stress States

Abstract The design of ductile heterogeneous metallic glasses (MGs) with enhanced deformability by purposely controlling the shear-band dynamics via modulation of the atomic-scale structures and local stress states remains a significant challenge. Here, we correlate the changes in the local atomic structure when cooling to cryogenic temperature with the observed improved shear stability. The enhanced atomic-level structural and elastic heterogeneities related to the nonaffine thermal contraction of the short-range order (SRO) and medium-range order (MRO) change the characteristics of the activation process of the shear transformation zones (STZs). The experimental observations corroborated by Eshelby inclusion analysis and molecular dynamics simulations disclose the correlation between the structural fluctuations and the change in the stress field around the STZ. The variations in the inclination axes of the STZs alter their percolation mechanism, affect the shear-band dynamics and kinetics, and consequently delay shear failure. These results expand the understanding of the correlation between the atomic-level structure and elementary plastic events in monolithic MGs and thereby pave the way for the design of new ductile metallic alloys.

scholarly journals Ultrathin Ni1− x Co x S2 nanoflakes as high energy density electrode materials for asymmetric supercapacitors

2019 ◽  
Vol 10 ◽  
pp. 2207-2216 ◽  
Author(s):  
Xiaoxiang Wang ◽  
Teng Wang ◽  
Rusen Zhou ◽  
Lijuan Fan ◽  
Shengli Zhang ◽  
...  
Keyword(s):  
Energy Density ◽  
Electrochemical Performance ◽  
Power Density ◽  
Active Sites ◽  
Electrode Materials ◽  
Specific Capacity ◽  
High Energy ◽  
High Energy Density ◽  
Oxide Material ◽  
Energy Storage Devices

Transition metal compounds such as nickel cobalt sulfides (Ni–Co–S) are promising electrode materials for energy storage devices such as supercapacitors owing to their high electrochemical performance and good electrical conductivity. Developing ultrathin nanostructured materials is critical to achieving high electrochemical performance, because they possess rich active sites for electrochemical reactions, shortening the transport path of ions in the electrolyte during the charge/discharge processes. This paper describes the synthesis of ultrathin (around 10 nm) flower-like Ni1− x Co x S2 nanoflakes by using templated NiCo oxides. The as-prepared Ni1− x Co x S2 material retained the morphology of the initial NiCo oxide material and exhibited a much improved electrochemical performance. The Ni1− x Co x S2 electrode material exhibited a maximum specific capacity of 1066.8 F·g−1 (533.4 C·g−1) at 0.5 A·g−1 and a capacity retention of 63.4% at 20 A·g−1 in an asymmetric supercapacitor (ASC). The ASC showed a superior energy density of 100.5 Wh·kg−1 (at a power density of 1.5 kW·kg−1), an ultrahigh power density of 30 kW·kg−1 (at an energy density of 67.5 Wh·kg−1) and excellent cycling stability. This approach can be a low-cost way to mass-produce high-performance electrode materials for supercapacitors.

scholarly journals Nitrogen-enriched graphene framework from a large-scale magnesiothermic conversion of CO2 with synergistic kinetics for high-power lithium-ion capacitors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Chen Li ◽  
Xiong Zhang ◽  
Kai Wang ◽  
Xianzhong Sun ◽  
Yanan Xu ◽  
...  
Keyword(s):  
Energy Density ◽  
High Power ◽  
Power Output ◽  
Large Scale ◽  
Electrode Materials ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Chemical Doping ◽  
Lithium Ion Capacitor

AbstractLithium-ion capacitors are envisaged as promising energy-storage devices to simultaneously achieve a large energy density and high-power output at quick charge and discharge rates. However, the mismatched kinetics between capacitive cathodes and faradaic anodes still hinder their practical application for high-power purposes. To tackle this problem, the electron and ion transport of both electrodes should be substantially improved by targeted structural design and controllable chemical doping. Herein, nitrogen-enriched graphene frameworks are prepared via a large-scale and ultrafast magnesiothermic combustion synthesis using CO2 and melamine as precursors, which exhibit a crosslinked porous structure, abundant functional groups and high electrical conductivity (10524 S m−1). The material essentially delivers upgraded kinetics due to enhanced ion diffusion and electron transport. Excellent capacities of 1361 mA h g−1 and 827 mA h g−1 can be achieved at current densities of 0.1 A g−1 and 3 A g−1, respectively, demonstrating its outstanding lithium storage performance at both low and high rates. Moreover, the lithium-ion capacitor based on these nitrogen-enriched graphene frameworks displays a high energy density of 151 Wh kg−1, and still retains 86 Wh kg−1 even at an ultrahigh power output of 49 kW kg−1. This study reveals an effective pathway to achieve synergistic kinetics in carbon electrode materials for achieving high-power lithium-ion capacitors.

Macro- to Atomic-Scale Tailoring of Si3N4 Ceramics to Enhance Properties

2005 ◽  
Vol 287 ◽  
pp. 233-241 ◽  
Author(s):  
Paul F. Becher ◽  
Gayle S. Painter ◽  
Naoya Shibata ◽  
Hua Tay Lin ◽  
Mattison K. Ferber
Keyword(s):  
Electronic Device ◽  
Atomic Level ◽  
Atomic Scale ◽  
Fracture Properties ◽  
Beta Particles ◽  
Preferential Segregation ◽  
Nitride Ceramics ◽  
Theoretical Predictions ◽  
The Matrix

Silicon nitride ceramics are finding uses in numerous engineering applications because of their tendency to form whisker-like microstructures that can overcome the inherent brittle nature of ceramics. Studies now establish the underlying microscopic and atomic-scale principles for engineering a tough, strong ceramic. The theoretical predictions are confirmed by macroscopic observations and atomic level characterization of preferential segregation at the interfaces between the grains and the continuous nanometer thick amorphous intergranular film (IGF). Two interrelated factors must be controlled for this to occur including the generation of the elongated reinforcing grains during sintering and debonding of the interfaces between the reinforcing grains and the matrix. The reinforcing grains can be controlled by (1) seeding with beta particles and (2) the chemistry of the additives, which also can influence the interfacial debonding conditions. In addition to modifying the morphology of the reinforcing grains, it now appears that the combination of preferential segregation and strong bonding of the additives (e.g., the rare earths, RE) to the prism planes can also result in sufficiently weakens the bond of the interface with the IGF to promote debonding. Thus atomic-scale engineering may allow us to gain further enhancements in fracture properties. This new knowledge will enable true atomic-level engineering to be joined with microscale tailoring to develop the advanced ceramics that will be required for more efficient engines, new electronic device architectures and composites.

Highly ordered nanoscale phosphomolybdate-grafted polyaniline/metal hybrid layered structures prepared via secondary sputtering phenomenon as high-performance pseudocapacitor electrodes

2021 ◽  
Author(s):  
Eun Seop Yoon ◽  
Bong Gill Choi ◽  
Hwan-Jin Jeon
Keyword(s):  
Electron Transfer ◽  
Aspect Ratio ◽  
Electrochemical Performance ◽  
High Aspect Ratio ◽  
High Performance ◽  
Electrode Materials ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
High Rate ◽  
Large Area

Abstract The development of energy storage electrode materials is important for enhancing the electrochemical performance of supercapacitors. Despite extensive research on improving electrochemical performance with polymer-based materials, electrode materials with micro/nanostructures are needed for fast and efficient ion and electron transfer. In this work, highly ordered phosphomolybdate (PMoO)-grafted polyaniline (PMoO-PAI) deposited onto Au hole-cylinder nanopillar arrays is developed for high-performance pseudocapacitors. The three-dimensional nanostructured arrays are easily fabricated by secondary sputtering lithography, which has recently gained attention and features a high resolution of 10 nm, a high aspect ratio greater than 20, excellent uniformity/accuracy/precision, and compatibility with large area substrates. These 10nm scale Au nanostructures with a high aspect ratio of ~30 on Au substrates facilitate efficient ion and electron transfer. The resultant PMoO-PAI electrode exhibits outstanding electrochemical performance, including a high specific capacitance of 114 mF/cm2, a high-rate capability of 88%, and excellent long-term stability.

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