一维碳纳米结构的有效合成及其在锂离子电池负极材料中的应用(英文)

采用热解处理已合成的聚吡咯纳米线实现一维碳纳米纤维的有效合成。在KOH的活化作用下,原始的纤维结构发生变化,获得带状碳纳米结构。对所合成的碳纳米线及碳纳米带进行形貌及结构表征。测试这两种一维碳纳米材料应于于锂离子电池中负极材料的电化学性能。结果表明,一维碳纳米线及一维碳纳米带均表现出较优的循环性能及良好的倍率性能。碳纳米线材料在循环50次后仍保持530 mA·h/g的可逆容量。在前23次充放电循环中,碳纳米带的可逆容量均高于850 mA·h/g,充放电循环到第23次的容量保持率为86%。     

Electrochemical and microstructural characterization of cyclic redox behaviour of SOFC anodes

The oxidation of Ni to NiO in solid oxide fuel cell (SOFC) anode will result in large bulk volume change, which may change the interfaces of the two phases in the anode cermet and thus may cause significant performance degradation. The reduction and oxidation (redox) of the Ni/YSZ cermet were studied at 800 ℃. Anodic polarization measurements were performed before and after redox cycles. The anode current density at an overpotential of 100 mV kept decreasing during the whole redox treatment. It decreased from 19.11 to 7.95 mA·cm-2 after two redox cycles. Anode supported unit cell was assembled for cell's discharge measurements. Cell performance declined after each redox cycle. The maximum power density decreased from 126.28 to 40.32 mW·cm-2 . The microstructural changes after redox cycling were recorded using scanning electron microscopy (SEM). The results reveal that after re-oxidation, the Ni gets coarse and has a higher porosity; the nickel network structure turns to be desultory.     

新型可充锂-空气电池的纳米刺状α-MnO_2/Pd空心微球催化剂(英文)

利用NaBH4溶液还原PdCl2的方法在具有纳米刺状表面的α-MnO2中空微球上沉积Pd,制备一种α-MnO2/Pd核壳型复合催化剂作为新一代可充锂-空气电池的催化剂。TEM、XRD和EDS等方法的分析结果表明,在催化剂中纳米Pd颗粒均匀地分布在刺状α-MnO2中空微球表面,Pd在催化剂中的质量分数约为8.88%。充放电测试结果表明,与纳米刺状的α-MnO2中空微球催化剂相比,α-MnO2/Pd复合催化剂提高了空气电极的能量转化效率和充放电循环性能。由Super P碳材料和所制备的α-MnO2/Pd复合催化剂所构成的空气电极在0.1mA/cm2电流密度下的首次放电比容量可以达1220 mA·h/g,经13次充放电循环后的容量保持率为47.3%。该纳米刺状α-MnO2/Pd核壳型复合催化剂是一种有前途的空气电池催化剂。     

Preparation and electrochemical properties of nanosized tin dioxide electrode material by sol-gel process

1　INTRODUCTIONTinoxideisawideenergy gapsemiconductorandhasfoundmanytechnologicalapplicationssuchascatalystsforoxidationoforganics,solid stategassen sorsandopticalelectronicdevices[1,2 ] .Recently ,sev eraltin oxide basedcompoundswerereportedtobegoodcandidatesasanodesforlithiumionbatteriesin steadofcarbonaceouselectrodes[36 ] ,theelectro chemicalreactionoccurringinthesecompoundsisnottheintercalationoflithiumintoahoststructure .Forbulksamplesofamorphousandcrystallinetinoxide ,adecomposition…     

Porous Hard Carbon Derived from Walnut Shell as an Anode Material for Sodium-Ion Batteries

Porous hard carbon with large interlayer distance was fabricated from walnut shells through a facile high-temperature pyrolysis process and investigated as an anode material for sodium-ion batteries (SIBs). The results show that the electrochemical performance is mainly dependent on the pyrolysis temperature. The porous hard carbon, which was carbonized at 1300°C, displays the highest reversible capacity of 230 mAh g^?1 at 20 mA g^?1 and an excellent cycling stability (96% capacity retained over 200 cycles). The promising electrochemical performances are attributed to the porous structure reducing distances for sodium ion diffusion and expanded interlayer spacing, which is beneficial for sodium reversible insertion/extraction. The excellent electrochemical performance as well as the low-cost and environmental friendliness demonstrates that walnut shell-derived porous hard carbon is a promising anode material candidate for SIBs.     

Preparation of Sb Doped Nano SnO2/Porous Ti Electrode and Its Degradation of Methylene Orange

利用热分解方法在多孔钛上制备了Sb掺杂纳米SnO2电极。也研究了该电极降解甲基橙的电化学性能。SEM和XRD测试表明,在多孔钛基体上可获得完整的、无裂缝的涂层。无裂缝的涂层表面由粒径范围在80~230 nm的Sb掺杂SnO2纳米颗粒组成。HRTEM测试结果表明,SnO2纳米颗粒由5~6 nm细小颗粒构成。在其余条件相同的情况下,强化寿命试验表明,Sb掺杂纳米SnO2 /多孔Ti电极的寿命远大于致密钛基体上的电极。Sb掺杂纳米SnO2 /多孔Ti电极可将浓度为100 mg/L的甲基橙溶液降解到8 mg/L,显示出该电极具有很强的有机物污染物电催化降解能力。并指出采用简单的表面处理技术,将使多孔钛具有很高的潜力被应用到有机污水降解领域     

3D MoS2/graphene nanoflowers as anode for advanced lithium-ion batteries

Vertical MoS₂ nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS₂ nanosheets and graphene by vertical channels enabled a high mechanical integrity of electrode and cycling stability. In particular, MoS₂/graphene nanoflowers anode delivered an ultrahigh specific capacity of 901.8 mA·h/g after 700 stable cycles at 1000 mA/g and a corresponding capacity retention as 98.9% from the second cycle onwards.     

Synthesis of Co_3O_4 Nanoparticles Wrapped Within Full Carbon Matrix as an Anode Material for Lithium Ion Batteries

A facile polyol-assisted pyro-synthesis method was used to synthesize Co_3O_4 nanoparticles embedded into carbon matrix without using any conventional carbon source. The surface analysis by scanning electron microscopy showed that the Co_3O_4 nanoparticles(~20 ± 5 nm) are tightly enwrapped within the carbon matrix. CHN analysis determined the carbon content was only 0.11% in the final annealed sample. The Co_3O_4@carbon exhibited high capacities and excellent cycling performance as an anode at various current rates(such as 914.4 and 515.5 mAh g~(-1) at 0.25 and1.0 C, respectively, after 50 cycles; 318.2 mAh g~(-1) at a high current rate of 5.0 C after 25 cycles). This superior electrochemical performance of the electrode can be attributed to the various aspects, such as,(1) the existence of carbon matrix, which acts as a flexible buffer to accommodate the volume changes during Li~+ion insertion/deinsertion and facilitates the fast Li~+and electron transfer and(2) the anchoring of Co_3O_4 nanoparticles within the carbon matrix prevents particles agglomeration.     

Alloy anodes for sodium-ion batteries

Sodium-ion batteries(SIBs) have emerged as one of the most promising candidates for next-generation energy storage systems because sodium is abundant in nature.The practical application of SIBs critically depends on developing robust electrode materials with high specific capacity and long cycling life,developing suitable anode materials is even more challenging.Alloy-type anodes are attractive for their high gravimetric and volumetric specific capacities,demonstrating great potential for high-energy SIBs,however,huge volume swelling hampered their practical application.Given the encouraging breakthroughs on alloy anodes for SIBs,herein,we present a review of the up-to-date progress and works carried out with alloy-based anode materials for SIBs.We review the synthetic strategies and their detailed electrochemical performance.In particular,we extensively reveal the important roles of alloy-based anodes in the development of SIBs.Research progress of alloy-type anodes and their compounds for sodium storage is summarized.Specific efforts to enhance the electrochemical performance of the alloy-based anode materials are discussed.Finally,we proposed multi-component alloys/high-entropy alloys(HEAs) as further research directions for alloy-based anodes.     

Sb2S3 nanorods/porous-carbon composite from natural stibnite ore as high-performance anode for lithium-ion batteries

To avoid the high purity reagents and high energy consumption involved in the manufacturing of lithium-ion battery anode materials, Sb₂S₃ nanorods/porous-carbon anode was prepared by remodeling natural stibnite ore with porous carbon matrix via a simple melting method. Due to the nanostructure of Sb₂S₃ nanorods and synergistic effect of porous carbon, the Sb₂S₃ nanorods/porous-carbon anode achieved high cyclic performance of 530.3 mA·h/g at a current density of 100 mA/g after 150 cycles, and exhibited a reversible capacity of 130.6 mA·h/g at a high current density of 5000 mA/g for 320 cycles. This shows a great possibility of utilizing Sb₂S₃ ore as raw material to fabricate promising anodes for advanced lithium-ion batteries.     

Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol

Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum utilization currently achieved in electrocatalytic systems. This electrode preparation consists of a two-step procedure: fLrst electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm^-2, which is 6.7 times higher than 7.6 mA.cm^-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4μm.     

Ingenious Interlacement of CoNiO2 on Carbon Nanotubes for Highly Stable Lithium-Ion Batteries

Nickel-cobalt oxide is considered as a promising anode for lithium-ion battery, owing to its high specific capacity, simple synthesis process and high safety. However, like most transition metal oxide anode materials, nickel-cobalt oxide suffers from poor conductivity, easy agglomeration and large volume expansion in the charging and discharging process, causing an inferior cycling lifespan. Here we report a structure design that CoNiO₂ particles are ingeniously interlaced on carbon nanotubes by a simple solvothermal method. These nanotubes are irregularly intertwined to obtain an independent electrode structure with high electronic conductivity, which can also alleviate the notorious volume expansion. Consequently, the corresponding lithium-ion battery shows superior electrochemical performance. It provides a discharge capacity of 1213.7 mAh g⁻¹ at 0.5 A g⁻¹, and can be stable over 100 cycles with a capacity retention of 96.45%. Furthermore, the battery can also deliver a reversible capacity of 544.8 mAh g⁻¹ at the high current density 3 A g⁻¹. This work provides a unique idea for the performance improvement of nickel-cobalt oxide anode for lithium-ion batteries.     

S-Doped Carbon-Coated FeS_2/C@C Nanorods for Potassium Storage

Potassium-ion batteries(PIBs) are promising scalable energy storage system;however,one of the challenges for its potential application is the huge volume variations during cycling due to the insertion/extraction of large size potassium ions.Here,we fabricated the S-doped carbon-coated rod-like FeS_2/C@C,which not only effectively alleviate the volume variations upon cycling but also can improve electrical conductivity and maintain the structural integrity.As an anode material for PIBs,the rod-like FeS_2/C@C electrodes delivered excellent rate performance(175 mA h g~(-1) at 0.5 A g~(-1)) and stable cycle performance(262 mA h g~(-1) after 100 cycles at 0.1 A g~(-1)).The superior excellent performance is associated with the unique structure of FeS_2/C@C.The as-synthesized FeS_2/C@C is demonstrated to be a potential anode for PIBs.     

Facile Synthesis of Yolk-Shell Bi@C Nanospheres with Superior Li-ion Storage Performances

Recently,exploring appropriate anode materials for current commercial lithium-ion batteries(LIBs) with suitable operating potential and long cycle life has attracted extensive attention.Herein,a novel anode of Bi nanoparticles fully encapsulated in carbon nanosphere framework with uniform yolk-shell nanostructure was prepared via a facile hydrothermal method.Due to the special structure design,this anode of yolk-shell Bi@C can effectively moderate the volume exchange,avoid the aggregation of active Bi nanoparticle and provide superior kinetic during discharge/charge process.Cycling in the voltage of 0.01-2.0 V,yolk-shell Bi@C anode exhibits outstanding Li+storage performance(a reversible capacity over 200 mAh g~(-1)after 400 cycles at 1.25 A g~(-1)) and excellent rate capability(a capacity of 404,347,304,275,240,199 and 163 mAh g~(-1) at0.05,0.1,0.25,0.5,1.0,1.8 and 3.2 A g~(-1),respectively).This work indicates that rational design of nanostructured anode materials is highly applicable for the next-generation LIBs.     

Na_2SnO_3掺杂TiO_2的结构及对TNT的降解研究

以钛酸丁酯为原料,Na_2SnO_3作为添加剂,通过溶胶-凝胶法制备了锐钛矿型TiO_2晶体,用XRD、FT-IR对催化剂进行了表征.红外光谱表明,Na_2SnO_3掺杂使得TiO_2粒子的晶格振动吸收峰向高波数移动6 cm~(-1),并出现明显的宽化.以含TNT废水为降解对象研究了所制备TiO_2的光催化活性.结果显示,所制备的SnO_3~(2-)掺杂TiO_2具有比P25更高的催化活性,10 h后降解率达到了96% (P25,88%).机制分析认为,SnO_3~(2-)在制备过程中通过热分解产生SnO_2,抑制TiO_2粒子在热处理过程中生长,有利于形成更细小的晶体,同时由于Sn~(4+)离子的影响,使微粒表面缺陷和活性比表面积增加,有利于提高光催化活性.     

双氧水水热处理泡沫镍制备 Ni(OH) 2 自集流超级电容器电极材料

目的寻找一种简便、价廉、对环境友好的方法制备具有高比容、长寿命的Ni(OH)2自集流超级电容器电极材料。方法采用水热法(15%(质量分数)的H2O2溶液,180℃,24 h)直接在泡沫镍集流体上原位生长Ni(OH)2,并对其形貌、组成以及电化学性能进行研究。结果通过双氧水水热处理,可以在泡沫镍集流体上原位生长出边长400~600nm、厚度约200nm的Ni(OH)2六边形片,此为六方晶的β-Ni(OH)2。该电极材料在2mol/LKOH溶液中的最高比容为2534F/g(扫速1mV/s),且循环1000圈后,比容值仍保持在91%以上(扫速为50mV/s)。结论该制备方法简单价廉,对环境友好,制得的电极材料具有自支撑、自集流的特点,且具有优异的电化学性能和良好的循环稳定性。     

钛基SnO2+SbOx电极固溶体生长活化能及作用机制

采用热分解法制备SnO2+SbOx钛基氧化物电极,利用TG/DTA、XRD和XPS等手段对SnO2+SbOx固溶体进行表征,计算SnO2+SbOx固溶体的生长活化能,并探讨SnO2+SbOx固溶体的作用机制,同时采用快速寿命法考察氧化物电极在0.5 mol/L H2SO4溶液中2 A/cm2下的预期使用寿命。结果表明： Sb掺杂SnO2形成的N型半导体和P型半导体产生的自由电子和氧空位使得电极导电性增强,预期使用寿命增加为30 h,晶粒表面氧空位的存在和非常低的晶间旋转驱动力是导致SnO2+SbOx固溶体的生长活化能降低为12.63 kJ/mol的主要原因。因此,Sb掺杂SnO2形成的电极固溶体是一种导电性好和稳定性高的电极材料。     

Synthesis of nano-sized Co<Subscript>3</Subscript>O<Subscript>4</Subscript> powder by spray conversion method for anode material of lithium battery

A nano-sized Co₃O₄ powder was prepared using a spray conversion method that could be applied for mass production. The spray-conversion process consisted of spray drying of a metallic liquid solution, a calcination treatment, and a ball milling process. The calcined Co₃O₄ powder consisted of agglomerated spherical clusters with nano-sized particles. After milling for 24 h, agglomerated powders were fragmented into fine powders sized below 60 nm. The lithium/cobalt oxide cell was charge-discharged at a constant current density of 0.2 mAcm⁻² and showed a first discharge capacity of 1100 mAhg⁻¹. The discharge capacity of the Li/Co₃O₄ cell drastically decreased with cycle number. By increasing the carbon content of the anode, the cycle life was improved. For a Co₃O₄ electrode containing 40 wt.% carbon, the discharge capacity was over 400 mAhg⁻¹ after 50 cycles. The spray conversion method might be a useful method to prepare nano-sized Co₃O₄ powder for the anode material of lithium batteries.     

Enhancing electrochemical performance of SnO2 anode with humic acid modification

Humic acid (HA) was studied as a modifier in the SnO₂ anode preparation for the electrochemical performance improvement. Scanning electron microscopy, 180° peel test, and nanoindentation experiment were used to examine the influence of the HA on electrode. The results showed that the addition of HA could improve the dispersion uniformity of all particles. The components were tightened, increasing the difficulty of peeling off the film from the current collector. The deformation resistance of the electrode was greatly enhanced by the HA modification. The electrochemical test results showed that the anode from the normal micron-sized SnO₂ particles with the HA modifier exhibited significant progress in electrochemical performance compared with those without HA. The reversible specific capacity of the SnO₂ anode can be maintained as high as 733.4 mA·h/g at a current density of 100 mA/g after 50 cycles. Therefore, HA is a promising modifier for anode preparation of lithium-ion batteries.     

3D Printing Engineered Multi-porous Cu Microelectrodes with In Situ Electro-Oxidation Growth of CuO Nanosheets for Long Cycle,High Capacity and Large Rate Supercapacitors

Developing excellent pseudocapacitive electrodes with long cycle,high areal capacity and large rate has been challenged.3 D printing is an additive manufacture technique that has been explored to construct microelectrodes of arbitrary geometries for high-energy–density supercapacitors.In comparison with conventional electrodes with uncontrollable geometries and architectures,3 D-printed electrodes possess unique advantage in geometrical shape,mechanical properties,surface area,especially in ion transport and charge transfer.Thus,a desirable 3 D electrode with ordered porous structures can be elaborately designed by 3 D printing technology for improving electrochemical capacitance and rate capability.In this work,a designed,monolithic and ordered multi-porous 3 D Cu conductive skeleton was manufactured through 3 D direct ink writing technique and coated with Cu O nanosheet arrays by an in situ electro-oxidation treatment.Benefiting from the highly ordered multiporous nature,the 3 D-structured skeleton can eff ectively enlarge the surface area,enhance the penetration of electrolyte and facilitate fast electron and ion transport.As a result,the 3 D-printed Cu deposited with electro-oxidation-generated CuO(3 DP Cu@Cu O) electrodes demonstrates an ultrahigh areal capacitance of 1.690 F cm~(-2)(38.79 F cm~(-3)) at a large current density of 30 m A cm-2(688.59 m A cm~(-3)),excellent lifespan of 88.20% capacitance retention after 10,000 cycles at 30 m A cm~(-2) and superior rate capability(94.31% retention,2-30 m A cm~(-2)).This design concept of 3 D printing multi-porous current collector with hierarchical active materials provides a novel way to build high-performance 3 D microelectrodes.