空间电容式分压装置高压探头电容稳定性的研究

运用模拟电荷法和有限元分析软件 ANSYS 对空间电容式分压装置的电容特性进行了数值计算,并对几种典型因素的影响进行了模拟计算。计算表明,在一定的环境条件下,这种分压装置能够提供较好的电容稳定性。

离子液体基凝胶电解质的制备及其在超级电容器中的应用

以大豆蛋白(SPI)和丙烯酰胺(AAm)复合交联制备出一种离子液体基凝胶聚合物电解质,并将其应用于超级电容器中,考察了超级电容器的电化学性能和可压缩性能。SPI与聚丙烯酰胺之间的协同作用,赋予凝胶电解质优异的压缩回弹性和耐疲劳强度,在经历80%的压缩应变100次循环后,仍可保持结构完整,应力保持率>80%,塑性变形率<15%,能量损耗系数<0.1。利用凝胶电解质组装的准固态超级电容器,具有优异的电化学性能,最大能量密度为25.99 W·h/kg,最大功率密度为3600 W/kg,且器件整体可承受80%的压缩应变而不发生断裂或损坏,表现出优良的可压缩性和电容稳定性。

大豆蛋白增强水凝胶电解质的制备及在全固态超级电容器上的应用

以聚丙烯酰胺链交联形成三维网状结构,通过大豆蛋白纳米粒子与聚丙烯酰胺之间的静电引力,将大豆蛋白引入聚丙烯酰胺交联网络中,经磷酸溶液置换,得到一种水凝胶电解质。大豆蛋白纳米粒子与聚丙烯酰胺分子链之间的协同作用,使得水凝胶在80%应变时进行100次的循环压缩后未发生结构断裂或损坏;以水凝胶电解质为固体电解质,以聚吡咯-碳纳米管纸为电极,组装成对称结构的全固态超级电容器。组装的全固态超级电容器具有优异的电化学性能,最大能量密度为6.2 W·h/kg,最大功率密度为398.4 W/kg。更重要的是,器件整体可承受80%的压缩应变而未产生断裂或损坏,并表现出良好的电容稳定性.

A 16 bit Stereo Audio ΣΔ A/D Converter

A 16 bit stereo audio novel stability fifth-order ∑△ A/D converter that consists of switched capacitor ∑△ modulators, a decimation filter, and a bandgap circuit is proposed. A method for the stabilization of a high order single stage ∑△ modulator is also proposed. A new multistage comb filter is used for the front end decimation filter. The ∑△ A/D converter achieves a peak SNR of 96dB and a dynamic range of 96dB. The ADC was implemented in 0. 5μm 5V CMOS technology. The chip die area occupies only 4. 1mm × 2.4mm and dissipates 90mW.

静电纺丝法制备纳米纤维基柔性电极研究进展

探讨静电纺丝法制备纳米纤维基柔性电极的研究现状。介绍了静电纺丝的理论和工作原理。从碳基、金属氧化物基、导电聚合物基3个主要研究方向,阐述了静电纺丝法制备柔性超级电容器纳米电极材料的最新研究进展,总结了不同纳米基电极材料的技术优势。认为:静电纺丝技术能够制备出具有较高功率密度和能量密度的柔性电极。

Structure and electrochemical hydrogen storage characteristics of La_(0.8-x)Pr_xMg_(0.2)Ni_(3.15)Co_(0.2)Al_(0.1)Si_(0.05) (x=0-0.4) electrode alloys

For the purpose of improving the electrochemical cycle stability of the La-Mg-Ni based A2BT-type electrode alloys, both reducing Mg content and substituting La with Pr were adopted. The Lao.8-xPrxMg0.2Ni3.15Co0.2A10.1Si0.05 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were fabricated by casting and annealing. The investigation on the structures and electrochemical performances of the alloys was performed. The obtained results reveal that the as-cast and annealed alloys comprise two major phases, （La, Mg）2Ni7 phase with the hexagonal Ce2NiT-type structure and LaNi5 phase with the hexagonal CaCus-type structure, as well as a little residual LaNi3 phase. It is also found that the addition of Pr element observably affects the electrochemical hydrogen storage characteristics of the alloys, just as the discharge capacity and high rate discharge ability （HRD） first rise then fall with the growing of Pr content, and among all the alloys, the as-cast and annealed （x=0.3） alloys generate the largest discharge capacities of 360.8 and 386.5 mA.h/g, respectively. Additionally, the electrochemical cycle stability of all the alloys markedly grows with the increase of Pr content. The capacity retaining rate （S100） at the 100th charging and discharging cycle is enhanced from 64.98% to 77.55% for the as-cast alloy, and from 76.60% to 95.72% for the as-annealed alloy by rising Pr content from 0 to 0.4. Furthermore, the substitution of Pr for La results in first increase and then decrease in the hydrogen diffusion coefficient （D）, the limiting current density （IL） as well as the electrochemical impedance.

Fundamental and Technical Challenges for a Compatible Design Scheme of Oxyfuel Combustion Technology

Oxyfuel combustion with carbon capture and sequestration （CCS） is a carbon-reduction technology for use in large-scale coal-fired power plants. Significant progress has been achieved in the research and development of this technology during its scaling up from 0.4 MWth to 3 MWth and 35 aWth by the combined efforts of universities and industries in China. A prefeasibility study on a 200 MWe large-scale demonstration has progressed well, and is ready for implementation. The overall research development and demonstration （RD＆D） roadmap for oxyfuel combustion in China has become a critical component of the global RD＆D roadmap for oxyfuel combustion. An air combustion/oxyfuel combustion compatible design philosophy was developed during the RD＆D process. In this paper, we briefly address fundamental research and technology innovation efforts regarding several technical challenges, including combustion stability, heat transfer, system operation, mineral impurities, and corrosion. To further reduce the cost of carbon capture, in addition to the large-scale deployment of oxyfuel technology, increasing interest is anticipated in the novel and next- generation oxyfuel combustion technologies that are briefly introduced here, including a new oxygen-production concept and flameless oxyfuel combustion.

Liquid-phase preparation and electrochemical property of LiFePO_4/C nanowires

Olivine LiFePO4/C nanowires have been successfully synthesized by a simple and eco-friendly solution preparation.The phase,structure,morphology and composition of the as-prepared products were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetric and differential-thermogravimetric analysis(TG-DTA) and energy dispersive X-ray spectrometry(EDS) techniques,showing uniform nanowire shape of LiFePO4/C with a diameter of 80-150 nm and a length of several microns.The heat-treated LiFePO4/C nanowires show excellent electrochemical properties of specific discharge capacity,rate capacity and cycling stability.In particular,the LiFePO4/C nanowires heat-treated at 400 °C show preferable first discharge specific capacity of 161 mA·h/g at 0.1C rate,while the voltage platform is 3.4 V and the first discharge specific capacity is 93 mA·h/g at 20C rate.The specific capacity retention is 98% after 50 cycles at 5C rate.

Research on Tian-Guang AC and DC Hybrid System Operation

This paper describes the transmission capability of Tian-Guang AC and DC hybrid system, as well as various operational effects on the transmission capability, such as HVDC modulation, AC voltage level and generating reserves. The study has shown that when both AC and DC systems operated in parallel, this system has higher transmission capability than operated separately, thus it satisfies stability criterion after the project put into operation.

Novel ionic liquid based electrolyte for double layer capacitors with enhanced high potential stability

Developing electrolyte with high electrochemical stability is the most effective way to improve the energy density of double layer capacitors(DLCs), and ionic liquid is a promising choice. Herein, a novel ionic liquid based high potential electrolyte with a stabilizer, succinonitrile, was proposed to improve the high potential stability of the DLC. The electrolyte with 7.5 wt% succinonitrile added has a high ionic conductivity of 41.1 m S cm^(-1) under ambient temperature, and the DLC adopting this electrolyte could be charged to 3.0 V with stable cycle ability even under a discharge current density of 6 A g^(-1). Moreover, the energy density could be increased by 23.4% when the DLC was charged to 3.0 V compared to that charged to 2.7 V.

High-capacity organic electrode material calix[4] quinone/CMK-3 nanocomposite for lithium batteries

Organic lithium-ion batteries（OLIBs） represent a new generation of power storage approach for their environmental benignity and high theoretical specific capacities.However, it has the disadvantage with regard to the dissolution of active materials in organic electrolyte. In this study, we encapsulated high capacity material calix[4]quinone（C4Q） in the nanochannels of ordered mesoporous carbon（OMC）CMK-3 with various mass ratios ranging from 1：3 to 3：1, and then systematically investigated their morphology and electrochemical properties. The nanocomposites characterizations confirmed that C4Q is almost entirely capsulated in the nanosized pores of the CMK-3 while the mass ratio is less than2：1. As cathodes in lithium-ion batteries, the C4Q/CMK-3（1：2） nanocomposite exhibits optimal initial discharge capacity of 427 mA h g^（-1） with 58.7% cycling retention after 100 cycles. Meanwhile, the rate performance is also optimized with a capacity of 170.4 mA h g^（-1） at 1 C. This method paves a new way to apply organic cathodes for lithium-ion batteries.

Oxygen vacancies boosting ultra-stability of mesoporous ZnO-CoO@N-doped carbon microspheres for asymmetric supercapacitors

Long-term cycling stability of pseudocapacitive materials is pursued for high-energy supercapacitors.Herein,the mesoporous zinc-cobalt oxide heterostructure@nitrogendoped carbon(ZnO-CoO@NC)microspheres with abundant oxygen vacancies are self-assembled through a hydrothermal method combined with an annealing post-treatment.The multifunctional polyvinyl pyrrolidone(PVP)is used as a structure-directing agent,the precursor of NC and the initiator of abundant oxygen vacancies in zinc-cobalt oxide microspheres.XPS demonstrates the generation of surface oxygen vacancies resulted from the reduction effect of conductive NC,and further confirms the weaker interaction between the metal ions and oxygen atoms.As a result,the electrode based on ZnO-CoO@NC in 2 mol L^-1 KOH shows enhanced capacitive performance with an excellent cycle stability of 92%retention of the initial capacitance after 40,000 charge-discharge cycles at 2 A g^-1,keeping the morphology unchanged.The assembled asymmetric supercapacitor,graphene//ZnO-CoO@NC,also performs good cyclic stability with 94%capacitance retention after 10,000 cycles at 2 A g^-1.The remarkable electrochemical performance of the self-assembled ZnO-CoO@NC composite is attributed to the mesoporous architecture,abundant oxygen vacancies,conductive ZnO scaffold for CoO crystals forming heterostructure of ZnO-CoO and the high conductive NC layer covering outside of the multi-metal oxide nanoparticles.Hence,the ZnO-CoO@NC holds great promise for high-performance energy storage applications.

Tailoring electrolyte enables high-voltage Ni-rich NCM cathode against aggressive cathode chemistries for Li-ion batteries

The LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(Ni-rich NCM)cathode materials suffer from electrochemical performance degradation upon cycling due to detrimental cathode interface reactions and irreversible surface phase transition when operating at a high voltage(≥4.5 V).Herein,a traditional carbonate electrolyte with lithium difluoro(oxalato)borate(Li DFOB)and tris(trimethylsilyl)phosphate(TMSP)as dual additives that can preferentially oxidize and decompose to form a stable F,B and Si-rich cathode-electrolyte interphase(CEI)that effectively inhibits continual electrolyte decomposition,transition metal dissolves,surface phase transition and gas generation.In addition,TMSP also removes trace H_(2)O/HF in the electrolyte to increase the electrolyte stability.Owing to the synergistic effect of Li DFOB and TMSP,the Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) half cells exhibit the capacity retention 76.3%after 500 cycles at a super high voltage of 4.7 V,the graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)full cells exhibit high capacity retention of 82.8%after 500 cycles at 4.5 V,and Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)pouch cells exhibit high capacity retention 94%after 200 cycles at 4.5 V.This work is expected to provide an effective electrolyte optimizing strategy compatible with high energy density lithium-ion battery manufacturing systems.

Enhanced energy storage properties and temperature stability of fatigue-free La-modified PbZrO3 films under low electric fields

Electrostatic energy^-storage capacitors,with their ultrahigh storage density and high temperature stability,have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low^-consumption systems.In such a context,this work reports on the successful production of anti^-ferroelectric(AFE)thin films with excellent energy storage performance under a relatively low electric field.In particular,La^-doped Pb Zr O3 thin films were fabricated using a sol^-gel method,yielding a recoverable energy storage density of 34.87 J cm^-3 with an efficiency of 59.23%at room temperature under the electric field of^800 k V cm^-1.The temperature dependence of the energy storage property was demonstrated from room temperature to 210°C,indicating a stable density variation between 34.87 and 27.98 J cm^-3.The films also exhibited excellent anti^-fatigue property(endurance of up to 3×10^9cycles and the recoverable energy storage density varied from 39.78 to 29.32 J cm^-3 combined with an efficiency of 61.03%–44.95%under the test frequencies from 10 to 5000 Hz).All results were obtained using compact films with a high polarization(Pmax)of approximately 103.7μC cm^-2 and low remnant polarization(Pr^7μC cm^-2),which was owing to the combination of La Ni O3 buffer layers and vacancies at Pb sites.These results illustrate the great potential of pulsed power devices in low^-consumption systems operating in a wide range of temperatures and long^-term operations.

NiCoSe2/Ni3Se2 lamella arrays grown on N-doped graphene nanotubes with ultrahigh-rate capability and long-term cycling for asymmetric supercapacitor

In this paper, we report a one-step electrodeposited synthesis strategy for directly growing NiCoSe2/Ni3Se2 lamella arrays(LAs) on N-doped graphene nanotubes(N-GNTs) as advanced free-standing positive electrode for asymmetric supercapacitors. Benefiting from the synergetic contribution between the distinctive electroactive materials and the skeletons, the as-constructed N-GNTs@NiCoSe2/Ni3-Se2LAs present a specific capacitance of ~1308 F g^-1 at a current density of 1 A g^-1. More importantly, the hybrid electrode also reveals excellent rate capability(~1000 F g^-1 even at 100 A g^-1) and appealing cycling performance(~103.2% of capacitance retention over 10,000 cycles). Furthermore, an asymmetric supercapacitor is fabricated by using the obtained N-GNTs@NiCoSe2/Ni3Se2LAs and active carbon(AC) as the positive and negative electrodes respectively,which holds a high energy density of 42.8 W h kg^-1 at 2.6 k W kg^-1, and superior cycling stability of ~94.4% retention over 10,000 cycles. Accordingly, our fabrication technique and new insight herein can both widen design strategy of multicomponent composite electrode materials and promote the practical applications of the latest emerging transition metal selenides in next-generation high-performance supercapacitors.