钬掺杂TiO_2/碳气凝胶电极电吸附光催化降解双酚A

采用浸渍法在碳气凝胶(CA)基底上负载了Ho掺杂TiO_2纳米颗粒,由SEM表征观察到CA为疏松多孔结构,Ho掺杂TiO_2粒径约为20 nm。XRD显示TiO_2为锐钛矿相。紫外-可见漫反射光谱显示,Ho掺杂TiO_2碳气凝胶的吸收带边红移至403 nm。在可见光照条件下,其光电流密度是Ho掺杂TiO_2/FTO的66倍。Ho掺杂TiO_2碳气凝胶电极进一步应用于对双酚A(BPA)废水的电吸附光催化降解,结果显示,在4.5 h内,双酚A的去除率达到了96.4%,在电吸附和光催化的协同作用下,实现了对双酚A模拟废水的高效降解。

碳凝胶/泡沫镍一体化电极用于高性能的超级电容器

以氧化石墨、间苯二酚、甲醛和泡沫镍为原料,经85 o C水热碳化处理,在泡沫镍表面原位聚合形成了碳凝胶/泡沫镍一体化电极,冷冻干燥处理后可得多孔碳凝胶/泡沫镍一体化电极.水系和有机系的超级电容器测试表明,多孔碳凝胶/泡沫镍一体化电极具有较高的比容量和良好的循环稳定性,其独特的一体化电极组成和多孔结构有利于电子和电解液离子的有效传输.

Designing Conformal Electrode-electrolyte Interface by Semi-solid NaK Anode for Sodium Metal Batteries

Solid-state Na metal batteries(SSNBs),known for its low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of NaK alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the intimate contact of electrode-electrolyte interface.Additionally,the filling of SiO_(2)nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 h.The full cell coupled with Na_(3)V_(3)(PO_(4))_(2)cathodes had an initial discharge capacity of 106.8 mAh·g^(-1)with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1)even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.

基于左右视野刺激范式的耳后SSVEP-BCI系统

目的基于稳态视觉诱发电位(steady-state visual evoked potential,SSVEP)范式的脑机接口(brain-computer interface,BCI)主要信号响应位于枕叶区,因而通常需要使用者洗头、佩戴脑电帽并辅助使用导电膏,给实际应用带来不便。耳后区域虽然可直接通过电极贴的方式快速开展SSVEP-BCI应用,但由于SSVEP在耳后区域的响应信号较弱,最终的系统性能受限。为提升SSVEP-BCI的耳后应用性能,本研究引入左右视野刺激范式,设计耳机与凝胶电极结合的采集方式,开发了一套便携性的耳后SSVEP脑机接口应用系统。方法系统由刺激与反馈端、数据采集端、数据处理系统3部分构成,其中刺激与反馈端实时进行SSVEP刺激及结果显示;数据采集端可实时获取耳后区域8通道的脑电数据,分别支持贴片湿电极及凝胶电极方案;数据处理系统对采集到的信号实时处理识别,并将结果反馈至刺激与反馈端。最终,为验证系统性能,研究分别采用湿电极与凝胶电极的系统方案在开放环境进行了标准SSVEP刺激与左右视野SSVEP刺激的在线对照试验。结果在线验证试验中,凝胶电极的采集方式达到95.8%±5.3%的识别正确率及(22.9±3.0)bits/min的信息传输速率,与耳后湿电极方案效果接近。且左右视野刺激范式较标准范式的识别正确率提高了40.9%,信息传输速率提高了14.3 bits/min。结论以上结果表明,基于左右视野刺激范式的耳后SSVEP-BCI系统取得了很好的应用效果,使用者可快速开展脑机交互应用,有望将SSVEP-BCI推广至更广泛的应用场景。

托利多pH计在蒸馏塔调和液中的应用

主要介绍了托利多pH计在蒸馏塔调和液的技改实验和控制方案,以及应用情况。

Synthesis of LiMnPO_4/C composite material for lithium ion batteries by sol-gel method

The LiMnPO4/C composite material was synthesized via a sol-gel method based on the citric acid. The X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical performance tests were adopted to characterize the properties of LiMnPO4/C. The XRD studies show that the pure olivine phase LiMnPO4 can be obtained at a low temperature of 500 °C. The SEM analyses illustrate that the citric acid used as the chelating reagent and carbon source can restrain the particle size of LiMnPO4/C well. The LiMnPO4/C sample synthesized at 500 °C for 10 h performs the highest initial discharge capacity of 122.6 mA-h/g, retaining 112.4 mA-h/g over 30 cycles at 0.05C rate. The citric acid based sol-gel method is favor to obtain the high electrochemical performance of LiMnPO4/C.

Preparation of dual-shell Si/TiO_(2)/CFs composite and its lithium storage performance

A dual-shell Si/TiO2/CFs composite was synthesized through a simple method to deal with the intrinsic drawbacks of silicon-based anode,in terms of huge volume change,unstable SEI films,and low electronic and ionic conductivity.The inner rigid TiO2 shell alleviates the huge volume expansion of the nano silicon,and the outer resilient carbon fiber,which is porous and staggered,is beneficial to the rapid transport of electrons and ions.The as-prepared Si/TiO2/CFs composite displays a superior reversible specific capacity of 583.4 mA·h/g,high rate capability and decent cycling performance.The dual-shell encapsulation method provides a guideline for other anode materials with huge volume expansion during the cycling process.

Synthesis of nanosize MnO_2 and its performence

Sol sol gel method and solid phase redox reaction were respectively applied in preparation of Nanosize MnO 2 powders. The experiments showed that only Mn 2O 3 could be obtained from ignition of Mn(Ⅱ) in the muffle furnace in air, and Mn 2O 3 had to be disproportionated in acids to gain MnO 2. The analysis of XRD and TEM technique revealed that the diameters of nanosize MnO 2 obtained by sol gel method was 35～45 nm and the x in MnO x was 1 9; the particle size of MnO 2 produced from solid phase redox reaction was 10～20 nm and the x in MnO x equaled 1 94. The test results have proved that the discharge property of alkaline manganese battery could be improved by nanosize MnO 2.

Preparation and electrochemical performance of Li_2Mn_(0.5)Fe_(0.5)SiO_4 cathode material with sol-gel method for lithium ion batteries

Li2Fe0.5Mn0.5SiO4 material was synthesized by a citric acid-assisted sol-gel method. The influence of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+) on the electrochemical properties of Li2Fe0.5Mn0.5SiO4 was studied. The final sample was identified as Li2Fe0.5Mn0.5SiO4 with a Pmn21 monoclinic structure by X-ray diffraction analysis. The crystal phases components and crystal phase structure of the Li2Fe0.5Mn0.4SiO4 material were improved as the increase of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+). Field-emission scanning electron microscopy verified that the Li2Fe0.5Mn0.5SiO4 particles are agglomerates of Li2Fe0.5Mn0.5SiO4 primary particles with a geometric mean diameter of 220 nm. The Li2Fe0.5Mn0.5SiO4 sample was used as an electrode material for rechargeable lithium ion batteries, and the electrochemical measurements were carried out at room temperature. The Li2Fe0.5Mn0.5SiO4 electrode delivered a first discharge capacity of 230.1 mAh/g at the current density of 10 mA/g in first cycle and about 162 mAh/g after 20 cycles at the current density of 20 mA/g.

Tuning Zn^(2+) coordination tunnel by hierarchical gel electrolyte for dendrite-free zinc anode

Aqueous zinc-ion batteries(ZIBs)are perceived as one of the most upcoming grid-scale storage systems.However,the issues of electrode dissolution,dendrite formation,and corrosion in traditional liquid electrolytes have plagued its progress.In this work,Zn dendrite growth and side reactions are effectively suppressed by a highly-confined tannic acid(TA)modified sodium alginate(SA)composite gel electrolyte(TA-SA).The ion-confinement effect is enhanced by divalent zinc ions coordinated with carboxyl groups and chelated with phenolic hydroxyl groups,thus guiding and regulating Zn deposition to achieve steady zinc plating/stripping behavior.As a consequence,the Zn/TA-SA/NH_(4)V_(4)O_(10) full cells deliver a high specific capacity of 238.6 mAh g^(-1) and maintain 94.51%over 900 cycles at 2 A g^(-1).Notably,after resting over 5 d,the capacity can be stabilized with a capacity retention of 97.25%after 200 cycles at 2 A g^(-1).This highlyconfined and hydrogen bond-strengthened gel electrolyte may provide an effective strategy for the future development of quasi-solid-state metal batteries.

One-step strategy to graphene/Ni（OH）2 composite hy- drogels as advanced three-dimensional supercapacitor electrode materials

Graphene-based three-dimensional （3D） macroscopic materials have recently attracted increasing interest by virtue of their exciting potential in electrochemical energy conversion and storage. Here we report a facile one-step strategy to prepare mechanically strong and electrically conductive graphene/Ni（OH）2 composite hydrogels with an interconnected porous network. The composite hydrogels were directly used as 3D supercapacitor electrode materials without adding any other binder or conductive additives. An optimized composite hydrogel containing -82 wt.% Ni（OH）2 exhibited a specific capacitance of -1,247 F/g at a scan rate of 5 mV/s and -785 F/g at 40 mV/s （-63% capacitance retention） with excellent cycling stability. The capacity of the 3D hydrogels greatly surpasses that of a physical mixture of graphene sheets and Ni（OH）2 nanoplates （-309 F/g at 40 mV/s）. The same strategy was also applied to fabricate graphene-carbon nanotube/Ni（OH）2 ternary composite hydrogels with further improved specific capacitances （-1,352 F/g at 5 mV/s） and rate capability （-66% capacitance retention at 40 mV/s）. Both composite hydrogels obtained here can deliver high energy densities （-43 and -47 Wh/kg, respectively） and power densities （-8 and -9 kW/kg, respectively）, making them attractive electrode materials for supercapacitor applications. This study opens a new pathway to the design and fabrication of functional 3D graphene composite materials, and can significantly impact broad areas including energy storage and beyond.

Transparent,stretchable and anti-freezing hybrid double-network organohydrogels

Stretchable ionic conductors with high transparency and excellent resilience are highly desired for flexible electronics,but traditional ionic conductive hydrogels are easy to dry and freeze.Herein,a newly hybrid crosslinking strategy is presented for preparing a stretchable and transparent hydrogel by using sodium alginate(SA)and acrylamide based on the unique physically and covalently hybrid crosslinking mechanism,which is transformed into organohydrogel by simple solvent replacement.Due to the combination of hybrid crosslinking double network and hydrogen bond interactions introduced by the glycerin-water binary solvent,the SA-poly(acrylamide)-organohydrogel(SPOH)demonstrates excellent anti-freezing(-20℃)property,stability(>2 days),transparency,stretchability(~1600%)and high ionic conductivity(17.1 mS cm^(-1)).Thus,a triboelectric nanogenerator made from SPOH(O-TENG)shows an instantaneous peak power density of 262 mW m^(-2)at a load resistance of 10 MΩand efficiently harvests biomechanical energy to drive an electronic watch and light-emitting diode.Moreover,The O-TENG exhibits favorable long-term stability(2 weeks)and temperature tolerance(-20℃).In addition,the raw materials can be prepared into SPOH fibers by a simple tubular mold method,exhibiting high transparency,which can be used for laser transmission.The various abilities of the SPOH promise the application of energy harvesting and laser transmission for wearable electronics and biomedical field.

Stable and low-resistance polydopamine methacrylamide-polyacrylamide hydrogel for brain-computer interface

Signal drift and performance instability of brain-computer interface devices induced by the interface failure between rigid metal electrodes and soft human skin hinder the precise data acquisition of electroencephalogram(EEG).Thus,it is desirable to achieve a robust interface for brain-computer interface devices.Here,a kind of polydopamine methacrylamide-polyacrylamide(PDMA-PAAM)hydrogel is developed.To improve the adhesion,dopamine is introduced into the polyacrylamide hydrogel,through the amino and catechol groups of dopamine in an organic-inorganic interface to build a covalent and non-covalent interaction.A strong attachment and an effective modulus transition system can be formed between the metal electrodes and human skin,so that the peeling force between the PDMAPAAM hydrogel and the porcine skin can reach 22 N m^(-1).In addition,the stable conductivity and long-term operating life of the PDMA-PAAM hydrogel for more than 60 days at room temperature are achieved by adding sodium chloride(NaCl)and glycerol,respectively.The PDMA-PAAM hydrogel membrane fabricated in this work is integrated onto a flexible Au electrode applied in a brain-computer interface.In comparison,the collected EEG signal intensity and waveform are consistent with that of the commercial counterparts.And obviously,the flexible electrode with PDMA-PAAM hydrogel membrane is demonstrated to enable a more stable and userfriendly interface.