可充锂空气电池多孔纳米催化剂

可充锂空气电池是当前化学电源研究热点和重点, 近年来取得了重要进展. 简要介绍了该领域在空气电极多孔纳米催化材料的设计与应用方面的最新研究成果, 讨论了碳、贵金属、氧化物三类催化材料的特征及性能, 展望了新型高效氧还原/氧析出双功能阴极纳米催化剂的发展方向.     

功率型锂/氟化碳一次电池的优化设计研究进展

锂/氟化碳电池作为固态正极中理论比能量较高（2203 Wh/kg）的一种一次电池体系,受到极大的关注,在诸多领域已有应用。本文对高功率锂/氟化碳电池的优化设计的最新研究进展进行了综述,详细讨论了氟化碳材料的前驱体、氟化方法、氟化碳材料表面改性、电极结构设计等因素对电池倍率性能的影响,并对今后功率型锂/氟化碳一次电池的发展方向进行了展望。     

CF_x-Ru复合阴极材料的制备及在锂一次电池中的应用（英文）

首次采用简单的原位化学改性方法合成了CFx-Ru复合阴极材料并应用于锂一次电池。与原始CFx材料相比,CFx-Ru在5C的放电倍率下放电容量、放电电压平台和最大功率密度可分别高达605 mAh·g^-1、2 V、8727 W·kg^-1。通过X射线衍射、X射线光电子能谱、扫描电子显微镜和透射电子显微镜对阴极材料结构、化学环境和形貌进行了研究。研究发现,在CFx-Ru复合材料中,nF/nC和C-F2键与C-F共价键的峰面积比都有所降低,这可能是由于RuO2与CFx材料表面或边缘的CF2惰性基团反应所致。这种原位化学反应消耗了非活性的CF2,产生了导电元素钌,并由于气相产物的演化而增加了比表面积。这些特性有助于改善阴极材料的电化学性能。电化学阻抗谱和N2吸附-脱附测试结果也进一步证实了改性材料拥有较大的比表面积和优异的电导率。     

可充镁电池有机电解液Mg(SnPh3)2的研究

合成了可用于可充镁电池的一种新型电解液Mg（SnPh3）2,其分解电压为1.2V（相对Mg参比）。循环伏安、交流阻抗和电化学性能测试结果表明用它作为可充镁电池的电解液,电池有较好的循环性能。     

一锅法制备Fe2O3@Fe-N-C氧还原电催化剂及其锌-空气电池的性能研究

在金属空气电池和燃料电池阴极上的氧还原反应(ORR)对相关电化学能量转换装置的整体性能有重要影响,金属-氮-碳催化剂有望替代传统的商业Pt-C成为新一代ORR电催化剂。本文通过简便的一步热解工艺合成了具有Fe-N_x活性位点和Fe₂O₃纳米颗粒共存的电催化剂,Fe₂O₃@Fe-N-C-1000催化剂在0.1 mol·L^-1 KOH溶液中表现出良好的ORR活性,半波电位为0.84 V,应用在锌-空气电池中时也具有可以和商业Pt-C媲美的性能,能量密度为88.3 mW·cm^-2,同时和Pt-C相比具有更好电化学稳定性,表现出优良的ORR应用潜力。     

核壳结构的Co3O4@δ-MnO2/Pt作为锂氧电池高效催化正极

通过简易、可控的水热方法在泡沫镍基体上直接生长了核壳结构的阵列型Co₃O₄@δ-MnO₂/Pt正极。阵列电极有利于电极的润湿、氧气的传输和Li₂O₂的负载。Co₃O₄@δ-MnO₂/Pt正极对氧还原和氧析出反应具有高的催化性能,可促使Li₂O₂依附Co₃O₄@δ-MnO₂/Pt阵列生长,从而保持阵列结构。该生长行为有利于Li₂O₂在充电时分解。以Co₃O₄@δ-MnO₂/Pt为催化正极的锂氧电池显示出高的容量（在电流密度100 mA·g^-1时容量为2 480 mAh·g^-1）,以及长的循环寿命（容量限定在500 mAh·g^-1时,在200 mA·g^-1电流密度下,可循环65次）,该性能超过了使用Co₃O₄或Co₃O₄@δ-MnO₂催化剂的电池。     

High Lithium Capacity MxV2O5Ay·nH2O for Rechargeable Batteries

The aqueous synthesis and electrochemical properties of nanocrystalline M_xV₂O₅A_y·nH₂O are described. It is easily and quickly prepared by precipitation from acidified vanadate solutions. M_xV₂O₅A_y·nH₂O has been characterized by X-ray powder diffraction, electron microscopy, TGA, chemical analyses, and electrochemical studies. The atomic structure is related to that of xerogel-derived V₂O₅·nH₂O. In M_xV₂O₅A_y·nH₂O, M is a cation from the starting vanadate salt and A is an anion from the mineral acid. This material exhibits high, reversible Li capacity and may be considered for use in a cathode in primary and secondary batteries. The lithium capacity of an electrode composed of M_xV₂O₅A_y·nH₂O/EPDM/carbon (88/4/8) is ∼380(mA h)/g (C/80 rate) and the energy density is ∼1000(W h)/kg (120-μm-thick cathode, 4-1.5 V, versus Li metal anode). Critical parameters identified in the synthesis of M_xV₂O₅A_y·nH₂O, with respect to achieving high Li-ion insertion capacity, are acid/vanadium ratio, starting vanadate salt, and temperature. Inclusion of carbon black in the synthesis yields a composite that maintains the high Li capacity, lowers the electrochemical-cell polarization, and preserves the lithium capacity at higher discharge rates. Li-ion coin cells, using pre-lithiated graphite anodes, exhibit electrochemical performance comparable to that of Li-metal coin cells.     

非水系二次锂-氧电池正极

非水系二次锂-氧电池(NRLOB)在当前所研发的二次电池中理论能量密度最高,但存在循环性能差,充、放电电流密度低等显著问题;这些问题主要同其氧正极上的电化学反应相关,关键在于过氧化锂Li₂O₂可逆生成、分解反应能否在较高的速率下连续地进行。本文综述了近年来NRLOB正极电化学反应机理、正极碳材料、催化剂和电极结构、电解液分解导致电极副反应等方面的研究现状;归纳了今后需要进一步研究的主要问题。     

Self-Assembly of Surface-Functionalized Ag1.8Mn8O16 Nanorods with Reduced Graphene Oxide Nanosheets as an Efficient Bifunctional Electrocatalyst for Rechargeable Zinc-Air Batteries

Bifunctional electrocatalysts play a key role in the performance of rechargeable metal-air batteries. Herein, we report a hybrid catalyst, Ag_1.8Mn₈O₁₆/rGO, self-assembled by Ag_1.8Mn₈O₁₆ nanorods and reduced graphene oxide (rGO) nanosheets through electrostatic attraction. The hybrid catalyst exhibits a better oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity than commercial Pt/C in alkaline medium. When employed as an air-cathode catalyst in Zn-air cells, the hybrids enabled higher and more stable output voltage and better durability of the cells, benefitting from the improved electrode conductivity, larger surface area, and synergetic coupling as a result of its high structural integrity.     

非水系锂空气电池碳基正极材料

锂空气电池因其极高的理论能量密度和环境友好等优点,有望成为下一代车用动力电源体系。然而,目前锂空气电池尚存在许多的问题和挑战,就正极而言,空气电极活性低的问题已成为制约锂空气电池技术发展最为重要的问题,因此,开发高性能锂空气电池正极催化剂一直以来都是该领域的重要研究课题。碳基催化剂(正极材料)是目前最具吸引力的锂空气电池正极材料之一,近年来得到了广泛的关注和研究。本文总结和介绍了近年来国内外在多孔碳基材料、石墨烯基材料、掺杂碳材料等碳材料作为锂空气电池正极材料方面的进展,包括本课题组在非水系锂空气电池正极材料方面的研究工作,并对碳基正极材料的发展及其在锂空气电池中的应用前景做了展望。     

One-step In-situ Synthesis of Vacancy-rich CoFe2O4@Defective Graphene Hybrids as Bifunctional Oxygen Electrocatalysts for Rechargeable Zn-Air Batteries

Developing efficient catalysts toward both oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) is the core task for rechargeable metal-air batteries. Although integration of two active components should be an effective method to produce the bifunctional catalysts in principle, traditional techniques still can not attain fine tunable surface structure during material-hybridization process. Herein, we present a facile short-time in-situ argon(Ar) plasma strategy to fabricate a high-performance bifunctional hybrid catalyst of vacancy-rich CoFe₂O₄ synergized with defective graphene(r-CoFe₂O₄@DG). Reflected by the low voltage gap of 0.79 V in two half-reaction measurements, the striking capability to catalyze ORR/OER endows it excellent and durable performance in rechargeable Zn-air batteries, with a maximum power density of 155.2 mW/cm² and robust stability(up to 60 h). Further experimental and theoretical studies validate its remarkable bifunctional energetics root from plasma-induced surface vacancy defects and interfacial charge polarization between DG and CoFe₂O₄. This work offers more opportunities for reliable clean energy systems by rational interfacial and defect engineering on catalyst design.     

Studies of Nano-sized Co_3O_4 as Anode Materials for Lithium-ion Batteries

Introduction　　Thelargecapacityandhighcellvoltageoflithium basedcells ,coupledwiththeirrelativelylowenvironmen talimpactmakethemanidealcandidateforportablepowersupplies .Studyonpresentmaterialsforlithiumionbatter iesfocusesonimprovingcycleabilityandincreasingca pacityofelectrodematerials.Asoneoftheimportantpartsoflithium ionbatteries ,anodematerialshavebeeninvestigatedintensively .Now ,carbonaceousmaterialsareusedinnearlyalllithiumionbatteriesbecauseoftheirhighcapacity (theoreticalcapaci tyof…     

Recycling Application of Li–MnO2 Batteries as Rechargeable Lithium–Air Batteries

The ever‐increasing consumption of a huge quantity of lithium batteries, for example, Li–MnO₂ cells, raises critical concern about their recycling. We demonstrate herein that decayed Li–MnO₂ cells can be further utilized as rechargeable lithium–air cells with admitted oxygen. We further investigated the effects of lithiated manganese dioxide on the electrocatalytic properties of oxygen‐reduction and oxygen‐evolution reactions (ORR/OER). The catalytic activity was found to be correlated with the composition of Li_xMnO₂ electrodes (0<x<1) generated in situ in aprotic Li–MnO₂ cells owing to tuning of the Mn valence and electronic structure. In particular, modestly lithiated Li_0.50MnO₂ exhibited superior performance with enhanced round‐trip efficiency (ca. 76 %), high cycling ability (190 cycles), and high discharge capacity (10 823 mA h g_carbon^?1). The results indicate that the use of depleted Li–MnO₂ batteries can be prolonged by their application as rechargeable lithium–air batteries.     

In-situ Grown SnO2 Nanospheres on Reduced GO Nanosheets as Advanced Anodes for Lithium-ion Batteries

Nanostructured tin dioxide (SnO₂) has emerged as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity (1494 mA h g⁻¹) and excellent stability. Unfortunately, the rapid capacity fading and poor electrical conductivity of bulk SnO₂ material restrict its practical application. Here, SnO₂ nanospheres/reduced graphene oxide nanosheets (SRG) are fabricated through in-situ growth of carbon-coated SnO₂ using template-based approach. The nanosheet structure with the external layer of about several nanometers thickness can not only accommodate the volume change of Sn lattice during cycling but also enhance the electrical conductivity effectively. Benefited from such design, the SRG composites could deliver an initial discharge capacity of 1212.3 mA h g⁻¹ at 0.1 A g⁻¹, outstanding cycling performance of 1335.6 mA h g⁻¹ after 500 cycles at 1 A g⁻¹, and superior rate capability of 502.1 mA h g⁻¹ at 5 A g⁻¹ after 10 cycles. Finally, it is believed that this method could provide a versatile and effective process to prepare other metal-oxide/reduced graphene oxide (rGO) 2D nanocomposites.