石墨基金属氧化物电极的电化学性能

采用热分解法制备了石墨基金属氧化物系列电极，用EDS表征了C／SnO2＋SbOx／MnO2电极的表层成分，考察了该电极在硫酸溶液中的使用寿命。用循环伏安曲线探讨了C／SnO2和C／SnO2＋SbOx／MnO2电极的析氧反应机理，同时计算了上述电极的析氧反应动力学参数和活化能。结果表明C／SnO2＋SbOx／MnO2电极在硫酸溶液中的使用寿命比石墨电极长，析氧反应活化能低（20kJ／mol），电催化性能良好，是酸性介质中一种优良的阳极材料。     

A designed core-shell structural composite of lithium terephthalate coating on Li4Ti5O12 as anode for lithium ion batteries

A core-shell structural composite was synthesized with lithium terephthalate（Li₂C₈H₄O₄） coated on spinel Li₄Ti₅O₁₂（LTO）. The composite displays a capacity of about 200 mA h g^-1 and a good rate capability with two charge/discharge platforms at 1.55 and 0.8 V. The excellent cycling performance of the composite is attributed to the successful combination of high cycling stability of LTO and high specific capacity of Li₂C₈H₄O₄. In addition, an interesting phenomena is observed for the first time for this composite which is that lithium ions transfer between LTO and Li₂C₈H₄O₄ at a fast speed. This is investigated in details via the asymmetric charge/discharge measurement and cyclic voltammogram（CV）.The LTO/Li₂C₈H₄O₄ composite may have potential applications to be used as an anode material for the electric vehicle batteries, which is shallowly charged/discharged at ordinary times using the charge/discharge platform of LTO and fully charged/discharged at emergency to release the extra high capacity from Li₂C₈H₄O₄.     

材料对锂离子电池热稳定性的影响

采用差示扫描量热法研究锂离子电池材料包括导电剂、粘结剂、电解液、Li0.5CoO2与LiC6对锂离子电池热稳定性的影响,并对由这些材料制备的063048型方形锂离子电池进行安全性测试.研究结果表明:锂离子电池的热稳定性受正极、负极及电解液3种因素的影响,电池热反应释放的热量由大到小顺序为:负极、正极、电解液.负极反应热主要来源于LiC6与粘结剂及电解液之间的反应,且与粘结剂的性质、用量及电解液用量有关;正极反应热主要来源于Li0.5CoO2的分解反应及其分解产生的氧气与有机溶剂之间的燃烧反应.聚偏二氟乙烯粘结剂比丙烯酸系水基粘结剂的热稳定性高,导电碳黑导电剂的热稳定性比乙炔碳黑导电剂的热稳定性高.过充实验结果表明,聚偏二氟乙烯粘结剂及导电碳黑能显著提高LiCoO2/石墨型锂离子电池的热稳定性.     

Nanostructure designing and hybridizing of high-capacity silicon-based anode for lithium-ion batteries

Lithium-ion batteries have long been used in electronic products and electric vehicles, but their energy density is slowly failing to keep up with demand. Because of its extraordinarily high theoretical specific capacity, silicon is regarded as the most potential next-generation anode material for practical lithium-ion batteries. However, its unavoidable volume expansion issue can cause electrode deformation and loss of electrical contact during cycling,resulting in significant performance reduc...     

A black phosphorus-graphite hybrid as a Li-ion regulator enabling stable lithium deposition

Lithium (Li) metal anodes have been regarded as the most promising candidates for high energy density secondary lithium batteries due to their high specific capacity and low redox potential. However, the issues of Li dendrites caused by nonuniform lithium deposition during battery cycling severely hinder the practical applications of Li metal anodes. Herein, a hybrid of black phosphorus-graphite (BP-G) is introduced to serve as an artificial protective layer for the Li metal anode. The two-dimensional few-layer BP, which is lithophilic, combined with the high electronic conductive graphite can act as a regulator to adjust the migration of Li ions, delivering a uniform and stable lithium deposition. As the growth of lithium dendrites is inhibited, the utilization of Li metal achieves > 98.5% for over 500 cycles in Li||Cu half cells, and the life span is maintained over 2000 h in Li||Li symmetric cells with a low voltage hysteresis of 50 mV. Moreover, the LiFePO₄||Li full cell with a BP-G Li-ion regulator presents significantly better specific capacity and cycling stability than that with the bare Li metal anode. Therefore, the introduction of the BP-G Li-ion regulator is demonstrated to be an effective approach to enable stable lithium deposition for rechargeable Li metal batteries.     

Direct growth of Fe3O4-MoO2 hybrid nanofilm anode with enhanced electrochemical performance in neutral aqueous electrolyte

To enhance the electrochemical energy storage performance of supercapacitors(SCs), the current researches are general directed towards the cathode materials. However, the anode materials are relatively less studied. In the present work, Fe_3O_4-MoO_2(FO-MO) hybrid nano thin film directly grown on Ti substrate is investigated, which is used as high-performance anode material for SCs in Li_2SO_4 electrolyte with the comparison to pristine Fe_3O_4 nanorod array. The areal capacitance of FO-MO hybrid electrode was initially found to be 65.0 m F cm~(-2)at 2 m Vs~(-1)and continuously increased to 260.0% after 50 cycles of activation. The capacitance values were considerably comparable or higher than many reported thinfilm iron oxide-based anodes in neutral electrolyte. With the protection of MoO_2 shell, the FO-MO electrode developed in this study also exhibited excellent cyclic stability(increased to 230.8% after 1000cycles). This work presents a promising way to improve the electrochemical performance of iron oxidebased anodes for SCs.     

新型成膜添加剂CH3COONH4对石墨负极电性能的改善

应用循环伏安和恒电流充放电等电化学方法,结合微观测试手段傅里叶变换红外光谱(FTIR)和扫描电镜(SEM),剖析了电解液中加入少量CH3COONH4后对电极表面SEI膜的影响.通过与空白溶液比较显示,添加CH3COONH4能显著提高天然石墨负极首次循环过程中的充放电容量,降低不可逆容量损失,提高电极的循环性能和倍率充放电性能.扫描电镜和电极表面SEI膜组分的FTIR分析表明,添加适宜浓度的CH3COONH4有助于改善天然石墨的电化学性能.     

Effect of Na~+ in situ doping on LiFePO_4/C cathode material for lithium-ion batteries

Li_1-XNaXFePO₄(X = 0, 0.01 or 0.05) composite cathode materials were synthesized by the simple solvothermal method. SEM images showed that Na doping had little effect on the morphology of particles, which provided a guarantee for its excellent electrochemical performance. Charge/discharge data revealed that an appropriate amount of doped Na could improve electrochemical performance. Li_0.99Na_0.01FePO₄ showed excellent rate capacity and cycle s...     

Low temperature synthesis of NiO/Co3O4 composite nanosheets as high performance Li-ion battery anode materials

NiO/Co3O4 composite nanosheets have been synthesized via a facile method at low temperature for the first time.The as prepared materials were characterized by X-ray powder diffraction(XRD) and transmission electron microscopy(TEM),and the performance of Li-ion batteries(LIBs) as anode materials were also studied.By controlling the atom ratio of Ni:Co,not only the size of the nanosheets can be controlled,the electrode’s conductivity and stability could also be greatly improved.The composite material showed a stable capacity retention during cycling(87% of the second capacity was retained after 15 cycles) even at a relatively large current rate(400 mA/g).The NiO/Co3O4 nanosheet might be promising candidate anode materials in high performance Li-ion batteries.     

苯砜用作碳酸丙烯酯基电解液添加剂的研究

研究了添加剂苯砜（PS）对碳酸乙烯酯（EC）做酸丙烯酯（PC）基电解质与石墨负极和LiCoO2正极相容性的影响．恒流充放电法和循环伏安法研究了PS对（c（LiPF6）=1mol／L）-EC／PC（体积比1：1）电解液与电极相容性的影响,XPS法分析了PS在改性人造石墨（MAG）电极上的还原产物．结果表明：EC／PC基电解质与MAG不相容,PS可以优先还原生成C6H5SO2Li和Li2SO2,抑制PC对MAG结构的破坏,促使EC／PC基电解质与MAG相容;EC／PC基电解质与MCMB的相容性不够理想,PS可以提高EC／PC基电解质与MCMB的相容性;PS可稍微改善EC／PC基电解质与LiCoO2的相容性．     

锂离子电池核型G@Cu0.85Sn0.15@C负极材料的改性

针对锡负极材料充放电过程中的体积效应,本文综合采用组分改性与结构改性的研究方法,合成Sn-Cu合金负极材料,研究Cu的掺入对Sn电化学稳定性的影响,同时基于优化改性的Sn-Cu合金开展核壳结构设计,研究最佳核壳结构构造工艺。结果表明,掺入Cu能在一定程度上改善Sn的循环稳定性,Sn-Cu样品的容量在60周循环后趋于稳定,库伦效率较高;核壳结构处理能大幅提升Sn-Cu合金负极材料的循环稳定性,采用球形改性天然石墨(d50=15μm)作为内核的样品首次放电比容量接近800mAh/g,充电比容量最大值超过了500mAh/g,100周容量保持率大于85%,最佳的核壳结构构造工艺是使用片状石墨作为内核,内核粒径为d50=15μm,外壳厚度为柠檬酸裂解碳占复合材料质量比的20%。核壳结构能将Sn-Cu合金的体积效应控制在“囚笼”式结构内,利于材料容量的发挥及循环稳定性的提升。核壳结构的可控制备对实现锡基合金负极材料的产业化具有重要的作用。     

新型蜂窝结构Si/Co3O4复合材料的研究

本文通过超声分散、水热生长和煅烧方法制备了新型蜂窝结构Si/Co3O4复合负极材料,在此基础上研究其复合结构与电化学性能的关系。采用X射线衍（XRD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对复合材料的物相、微观形貌进行表征,并采用电化学手段对其性能进行测试。结果表明：硅纳米颗粒主要分布于Co3O4蜂窝孔洞结构的内层;相比于纯Si负极材料,蜂窝结构Si/Co3O4复合材料具有更好的结构稳定性、倍率性能和循环性能,首次放电比容量为1475 mAh g-1,第二次维持在851 mAh g-1,经过75 次循环后放电比容量仍有 802 mAh g-1,较第二次比容量损失率仅为0.17%/周,这主要是归因于硅纳米颗粒和Co3O4之间存的空隙为Si负极嵌锂过程中的体积膨胀提供了空间,有效缓冲Si负极的体积变化。     

Li4Ti5O12纳米球改性天然石墨及其电性能研究

用溶胶凝胶法对天然石墨（NG）进行表面改性处理,即在NG表面形成Li4Ti5O12（LTO）纳米球包覆层,并对其电性能进行了研究。分析表明,LTO纳米球在石墨表面单分散均匀分布,粒径为50-150 nm。此表面改性,提高了NG的首次效率及克容量,分别为1.4%和37.9 mAh/g;全电池测试结果发现,LTO改性后,在2.4-2.8 V之间的副反应明显减少,即石墨表面结构破坏减少、不可逆容量减少,从而提高了首次效率及克容量。     

Double carbon decorated lithium titanate as anode material with high rate performance for lithium-ion batteries

Spinel lithium titanate(Li_4Ti_5O_(12)) has the advantages of structural stability, however it suffers the disadvantages of low lithium-ion diffusion coefficient as well as low conductivity. In order to solve issues,we reported a simple method to prepare carbon-coated Li_4Ti_5O_(12)/CNTs(C@Li_4Ti_5O_(12)/CNTs) using stearic acid as surfactant and carbon source to prepare carbon coated nanosized particles. The obtained Li_4Ti_5O_(12) particles of 100 nm in size are coated with the carbon layers pyrolyzed from stearic acid and dispersed in CNTs matrix homogeneously. These results show that the synthesized C@Li_4Ti_5O_(12)/CNTs material used as anode materials for lithium ion batteries, presenting a better high-rate performance(147 m Ahg~(-1)at20 C). The key factors affecting the high-rate properties of the C@Li_4Ti_5O_(12)/CNTs composite may be related to the synergistic effects of the CNTs matrix and the carbon- coating layers with conductivity enhancement. Additionally, the amorphous carbon coating is an effective route to ameliorate the rate capability of Li_4Ti_5O_(12)/CNTs.     

MnO@CoMn$_{\textbf{2}}$O$_{\textbf{4}}$/N-C纳米线复合材料的制备及其作为锂离子电池阳极材料的电化学性能

过渡金属氧化物作为锂离子电池(lithium-ion batteries, LIBs)阳极材料时具有较高的理论容量, 但因其电导率低, 以及充放电过程中的体积膨胀效应常会导致容量的快速衰减. 碳包覆是提升金属氧化物导电性的有效方法, 二者之间的协同效应也可以有效提升材料的电化学性能. 以MnO$_{2}$纳米线为模板制备出MnO$_{2}$@ZIF-67有机-无机杂化纳米结构, 再通过退火处理合成了氮掺杂碳包覆的MnO@CoMn$_{2}$O$_{4}$纳米线复合材料(MnO@CoMn$_{2}$O$_{4}$@N-C). ZIF-67的有机配体在高温煅烧过程中发生碳化反应, 产生了氮掺杂碳, 提升了导电性. 当作为锂离子电池阳极材料时, MnO@CoMn$_{2}$O$_{4}$/N-C纳米线复合材料在0.1 A/g电流密度下的首次放电比容量为1 594.6 mA$\cdot$h/g, 并且在100次充放电循环后的放电比容量仍保持在 925.8 mA$\cdot$h/g, 在0.5 A/g电流密度下经200次充放电循环后的放电比容量仍维持在837.6 mA$\cdot$h/g, 同时具有优异的倍率循环性能. 这种优异的电化学储能特性主要来源于复合材料的特殊结构, 以及氮掺杂碳的包覆.     

A facile method to synthesize 3D structured Sn anode material with excellent electrochemical performance for lithium-ion batteries

Sn anode materials with high specific capacity are an appealing alternative to graphite for next-generation advanced lithium-ion batteries. However, poor electrochemical performance originating from fracture and pulverization due to the enormous volume changes during lithium alloying/dealloying hinders their commercial applications. Here, we propose the synthesis of a novel 3D structured Sn anode material by a facile method: heat treatment of nanosized SnO₂ spheres in a tube furnace w...     

Sodium-ion capacitors with superior energy-power performance by using carbon-based materials in both electrodes

Na-ion capacitors(NICs) are promising energy storage devices in virtue of their merits in combining the high energy densities of secondary batteries and the high power densities of supercapacitors.However,it is still very challenging to achieve a balanced energy-power performance in NIC device due to the kinetic imbalance between the battery-type anode and the capacitive-type cathode.In this work,an NIC device based on carbon materials for both anode and cathode has been reported.As-prepared(polyimide/graphene oxide)-derived carbon(PIGC) anode material shows excellent rate capability,which can deliver a specific capacity of 110 mAh g~(-1) at high current densities of 5 A g~(-1).In addition,the N,B co-doped expanded reduced graphite oxide(NBEG)cathode demonstrates a high specific capacitance of 328 F g~(-1).Due to the improved rate capability of PIGC anode and specific capacitance of NBEG cathode,the imbalance on the energy and power densities between anode and cathode is well addressed.As-assembled PIGC//NBEG device can deliver an energy density of 55 W h kg~(-1) even at a high power density of 9500 W kg~(-1).The energy-power properties of PIGC//NBEG are superior to many state-of-the-art NIC devices that using carbon or non-carbon based electrodes.This work offers not only a promising device configuration with superior energy-power properties,but also a guidance for the design strategies on electrode materials for high-throughput energy storage systems.     

SrF2颗粒涂覆增强Si/C负极电化学性能

The silicon-based material exhibits a high theoretical specific capacity and is one of the best anode for the next generation of advanced lithium-ion batteries (LIBs). However, it is difficult for the silicon-based anode to form a stable solid-state interphase (SEI) during Li alloy/de-alloy process due to the large volume change (up to 300%) between silicon and Li_4.4Si, which seriously limits the cycle life of the LIBs. Herein, we use strontium fluoride (SrF₂) particle to coat the silicon?carbon (Si/C) electrode (SrF₂@Si/C) to help forming a stable and high mechanical strength SEI by spontaneously embedding the SrF₂ particle into SEI. Meanwhile the formed SEI can inhibit the volume expansion of the silicon?carbon anode during the cycle. The electrochemical test results show that the cycle performance and the ionic conductivity of the SrF₂@Si/C anode has been significantly improved. The X-ray photoelectron spectroscopy (XPS) analysis reveals that there are fewer electrolyte decomposition products formed on the surface of the SrF₂@Si/C anode. This study provides a facile approach to overcome the problems of Si/C electrode during the electrochemical cycling, which will be beneficial to the industrial application of silicon-based anode materials.     

高容量型锂离子电池硅基负极材料的研究进展

硅基负极材料由于其具有高容量而被广泛研究,该材料在充/放电过程中巨大的体积变化、低的循环寿命和初始库仑效率阻碍了其商业化应用. 本文分析了硅基负极材料的工作原理,回顾了其在脱/嵌锂过程中的晶体结构、表面/界面的变化以及提高其电化学性能的方法,讨论了锂离子电池硅基负极材料的前景.     

NiFe2O4基金属陶瓷材料的制备及其耐腐蚀性能

采用传统粉末冶金技术制备了铝电解用Cu-NiFe2O4和Ni-NiFe2O4金属陶瓷惰性阳极,并对其在Na3AlF6-Al2O3熔体中的腐蚀行为进行了研究.研究结果表明:NiFe2O4基金属陶瓷阳极的腐蚀行为与热力学计算结果吻合;金属Cu与NiFe2O4陶瓷的润湿性能不好,Cu-NiFe2O4金属陶瓷的致密化和导电性能难以提高;致密度过低时,会导致金属相高温氧化和电解质浸渗,电极肿胀、开裂;在电解过程中,5%Cu-NiFe2O4存在金属相聚集和在陶瓷基体中Fe优先溶解的现象,但金属铜并未发生阳极溶解;5%Ni-NiFe2O4金属陶瓷易实现致密化烧结,在电解过程中表现出良好的耐腐蚀性能,会发生金属Ni的阳极溶解,并存在陶瓷基体中铁优先溶解的现象.