锂离子电池硅/石墨烯负极材料的电化学性能

采用高能球磨法制备了纳米硅/石墨烯(Si@G)复合锂离子电池负极材料,并研究了高能球磨时间对Si@G复合材料成分和电化学性能的影响。X射线衍射分析结果表明:球磨40 min后,产物中出现少量电化学惰性的碳化硅。球磨20 min的Si@G复合材料具有最高的首次放电比容量(3 418 mA?h/g)和首次Coulomb效率(89%),但其充放电循环稳定性较差,放电比容量在33次充放电后即衰减为首次的80%。而球磨40 min的Si@G复合材料,充放电84次后,其容量保持率仍为80%。表明没有储锂容量的杂质相SiC虽然导致Si@G负极材料的首次充放电比容量下降,但有利于提高充放电循环稳定性。     

锂离子电池用硅-石墨/炭复合负极材料的电化学性能研究（英文）

以纳米硅、石墨和马铃薯淀粉为原料制备硅-石墨/炭复合负极材料,探讨复合材料的制备工艺对其电化学性能的影响,并采用扫描电镜和X-射线衍射法对材料的颗粒形貌和微晶结构进行表征。研究表明:当复合材料中m(Si)/m(graphite)为1∶4,球磨时间为10 h时,复合材料经20次循环后其可逆容量仍为466 mA·h/g,显示出良好的电化学性能,进一步分析表明纳米硅和石墨均对复合材料的可逆容量做出贡献,而且复合材料中含量较高的石墨的颗粒形貌和微晶结构对其电化学性能起关键性作用。     

热处理对锂离子电池硅/石墨/炭负极电化学性能的影响

将天然石墨、酚醛树脂和微米级硅粉进行球磨处理制备复合材料前驱物,再于N2气氛下700℃炭化得到硅/石墨/炭(Si/G/C)复合电极材料,采用X射线衍射仪、扫描电镜和透射电镜及电化学循环充放电对其形貌、结构及其电化学性能进行表征.结果表明,Si/G/C作为锂离子电池负极材料具有高于900 mA·h/g的可逆比容量,40次循环后保持在550 mA·h/g.对电极进行热处理后,其循环性能显著提高,40次循环后比容量保持在700 mA· h/g.扫描电镜分析结果显示,热处理后集流体上电极材料分布更均匀,因涂抹不均形成的空隙不复存在.热处理后电极结构更致密、内部黏结强度增大使其结构稳定性明显提升,是电极循环性能提高的主要原因.     

电力系统储能中的多孔碳电池材料及应用实验研究

针对电化学储能中的高能二次电池的经济效益、容量和稳定性等问题，提出一种制备Si/C@GR/G复合材料的方法和电池电极片工艺优化，并对其性能进行研究。实验结果表明，制备的包覆型碳硅复合材料能够减少电解液消耗，提高材料活性和电池容量；石墨烯的最佳掺量为5%，石墨烯二次包裹覆盖Si/C复合材料，此时，电池充放电过程中每次循环的电流及其增幅较强，材料表现出较好的活化反应和导电性，电池活性最佳；复合材料中纳米硅含量为10%时，电池表现出高容量、较好的充放电循环稳定性、安全性等优点。综上，制备的Si/C@GR/G多孔碳电池复合材料，不仅成本低，安全环保，还可以有效提高锂离子电池的容量、循环稳定性，表现出良好的电化学综合性能。     

硅基负极材料研究开发与产业化进展

硅基负极材料比容量是石墨和钛酸锂的理论比容量的10倍,电位比相应的石墨材料高0.15V,是可替代石墨的新型负极材料。硅基负极材料存在的应用问题是体积膨胀效应,解决办法是纳米化和做成复合材料。日立麦克赛尔和三井金属已经工业化生产这种负极材料。     

球磨法制备SnO_2/石墨复合材料及其电化学性能

利用球磨法制备了氧化锡（SnO2）/石墨复合材料,采用场发射扫面电镜、X射线衍射和比表面积对样品进行表征,结果显示,SnO2颗粒包裹在石墨片层上,SnO2/石墨复合材料的比表面积为83.90 m2/g。电化学测试结果表明,球磨法制备的SnO2/石墨复合材料首次放、充电容量分别为1 749mA h/g和1 346 mA h/g,在50 mA/g,100 mA/g和500 mA/g电流密度下,循环40次后,该电极可逆放电容量仍然高达432 mA h/g。     

锂离子电池硅/热解聚苯胺复合负极材料的研究

以纳米硅为原料,聚苯胺（PANI）为碳源,通过球磨法和高温热解制备了硅/热解聚苯胺（Si/p-PANI）复合物作为锂离子电池负极材料,并研究了热解温度对复合材料性能的影响。采用XRD、SEM、TEM、FTIR及XPS方法对复合材料的结构、形貌和组成进行了表征;采用恒流充放电和CV等方法测试了材料的电化学性能。研究结果表明,Si/p-PANI可以抑制纳米硅颗粒之间的团聚,并形成良好的导电网络。700℃热解后得到的Si/p-PANI在400 mA·g^-1电流密度下循环50次,可逆比容量为1 051.1 mAh·g^-1,具有良好的电化学性能。     

不同导电剂对硅碳复合负极性能的影响

导电剂的添加对负极材料在电池的循环性能中能否发挥其最优的性能起重要作用。文章以纳米硅碳复合负极材料为研究对象,研究了KS-6(导电炭黑)及SUPER-P(导电石墨)两种导电剂对硅碳复合负极材料电化学性能的影响。通过扫描电镜、电池测试系统分析了两种导电剂、负极片的形貌及负极片的电化学性能。结果表明添加粒度细小的球形状的SUPER-P的极片所表现出来的循环性能及大电流放电性能更好,其中首效可达到91.1%,循环50次容量保持率达到96.2%,600mA/g电流放电时比容量为178.5mAh/g。     

纳米硅碳/石墨复合负极材料的制备及其电化学性能研究

以机械球磨法和化学气相沉积法制备的纳米硅为原料，通过喷雾干燥法制备了人造石墨@纳米硅@无定形碳材料，探究不同制备工艺的纳米硅对包覆效果的影响。结果表明，气相沉积法制备的球形硅颗粒包覆效果更好，材料的电化学性能更优，在0.1C倍率下循环150周，比容量维持在678.7 mAh·g^-1。     

硅/氧化硅/锡/碳锂离子电池负极复合材料制备及电化学性能

以一氧化硅、二氧化锡和导电碳(Super P)为原料,通过高能球磨,加入稀盐酸与糠醇发生聚合反应,再采用高温固相法制得硅/氧化硅/锡/碳复合材料作为锂离子电池负极材料.用 XRD、SEM 进行表征,并进行有关电化学性能测试,首次放电比容量高达 1503 mAh·g<'-1>,循环性能得到了较大改善.     

Structural and electrochemical characterization of Fe–Si/C composite anodes for Li-ion batteries synthesized by mechanical alloying

A Fe–Si (FeSi₂ + Si)/C composite was prepared by mechanical ball milling and investigated as a new inserting anode for use in Li-ion batteries. The composite so prepared has a sandwich structure with the alloy particles as middle cores and the graphite layer as outer shells. The charge-discharge measurements revealed that the Fe–Si/C composite not only had a quite high initial capacity of approximately 680 mAh g⁻¹, but also exhibited greatly improved capacity retention with a reversible capacity of approximately 500 mAh g⁻¹ after 15 cycles in comparison with pure Si and Fe–Si alloy. Based on XRD, XPS, SEM, Raman and EIS analysis of the composite electrode in different lithiated states, the mechanism for improved cycleability is found to be due to the effective buffering of the volumetric changes of the Fe–Si particles by the graphite shell.     

Electrochemical performances of Al-based composites as anode materials for Li-ion batteries

Al-C, Al-Fe and Al-Fe-C composite materials have been prepared by high-energy ball milling technique. The electrochemical measurements demonstrated that the Al-Fe-C composites have greatly improved electrochemical performances in comparison with Al, Al-C and Al-Fe anode. For example, Al₇₁Fe₉C₂₀ can deliver the reversible capacity of 436 mAh g⁻¹ at first cycle and 255 mAh g⁻¹ at 15th cycle. This improved electrochemical performance could be attributed to the alloying formation of Al with Fe and the buffering effect by the graphite matrix. This suggests that the Al-Fe-C composite has a potential possibility to be developed as an anode material for lithium-ion batteries.     

Polymer microsphere embedded Si/graphite composite anode material for lithium rechargeable battery

Si/graphite composite materials embedded with polymer microsphere as an elastic inactive phase were prepared by high-energy mechanical milling and investigated as a high capacity anode material for lithium rechargeable battery. Improved capacity retention was achieved with the composite. In situ measurement of the electrode thickness revealed that the swelling of the electrode became smaller with the increase of polymer microsphere content. It is believed that polymer microsphere played a buffering role of accommodating the mechanical strains induced by silicon expansion during lithiation, resulting in the suppression of the volume expansion of the electrode, which improved the cycle performance of the electrode.     

Composite anode material of silicon/graphite/carbon nanotubes for Li-ion batteries

A composite anode material of silicon/graphite/multi-walled carbon nanotubes (MWNTs) for Li-ion batteries was prepared by ball milling. This composite anode material showed a discharge capacity of 2274 mAh/g in the first cycle, and after 20 charge-discharge cycles, a reversible capacity of 584 mAh/g was retained, much higher than 218 mAh/g for silicon/graphite composite. It was observed that silicon particles were homogeneously embedded into the “lamellar structures” of flaked graphite particles, and the silicon/graphite composite particles were further wrapped by a MWNTs network. The improvement in the electrochemical properties of the composite anode material was mainly attributed to the excellent resiliency and good electric conductivity of the MWNTs network.     

Electrochemical reaction of the SiMn/C composite for anode in lithium ion batteries

The SiMn-graphite composite powder was prepared by mechanical ball milling and its electrochemical performances were evaluated as the candidate anode materials for lithium ion batteries. It is found that the cyclic performance of the composite materials is improved significantly compared to SiMn alloy and pure silicon. The heat treatment of the electrodes is beneficial for enhancing the cyclic stabilities. The SiMn-20 wt.% graphite composite electrode after annealing at 200 °C has an initial reversible capacity of 463 mAh g⁻¹ and a charge-discharge efficiency of 70%. Moreover, the reversible capacity maintains 426 mAh g⁻¹ after 30 cycles with a coulomb efficiency of over 97%. The phase structure and morphology of the composite were analyzed by X-ray diffraction (XRD) and scanning electron microscopy. The lithiation/delithiation behavior was investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The composite materials appear to be promising candidates as negative electrodes for lithium rechargeable batteries.     

Effect of milling method and time on the properties and electrochemical performance of LiFePO4/C composites prepared by ball milling and thermal treatment

Effects of ball milling way and time on the phase formation, particulate morphology, carbon content, and consequent electrode performance of LiFePO₄/C composite, prepared by high-energy ball milling of Li₂CO₃, NH₄H₂PO₄, FeC₂O₄ raw materials with citric acid as organic carbon source followed by thermal treatment, were investigated. Three ball milling ways and five different milling durations varied from 0 to 8 h were compared. LiFePO₄/C composites could be obtained from all synthesis processes. TEM examinations demonstrated LiFePO₄/C from ball milling in acetone resulted in sphere shape grains with a size of ∼60 nm, similar size was observed for LiFePO₄/C from dry ball milling but in a more irregular shape. The ball milling in benzene resulted in a much larger size of ∼250 nm. The LiFePO₄/C composites prepared from dry ball milling and ball milling in acetone showed much better electrochemical performance than that from ball milling in benzene. SEM examinations and BET measurements demonstrated that the high-energy ball milling effectively reduced the grain size. A ball milling for 4 h resulted in the best electrochemical performance, likely due to the proper amount of carbon and proper carbon structure were created.     

球磨对Mg_(1.8)Al_(0.2)Ni_(0.8)Mn_(0.2)合金性能影响的研究

分别采用固相扩散法和随后球磨两步法制备Mg1.8A l0.2N i0.8Mn0.2型贮氢合金,研究了球磨对合金相的形成和其电化学性能的影响。SEM测试显示,球磨过程有利于非晶相的形成。充放电测试表明,在100 mA/g放电电流条件下,经过球磨后的合金最高放电容量可达110 mAh/g左右,而单纯固相扩散法合成的合金放电容量约为80mAh/g。循环寿命测试,球磨的样品经过50次循环其容量衰减到40%,非球磨样品经25次的循环即衰减到同样程度。合金的电化学性能的改善与球磨中结构变化所产生的晶体缺陷有关。     

Nano-porous Si/C composites for anode material of lithium-ion batteries

Nano-porous silicon composite incorporated with graphite and pyrolyzed carbon was synthesized and investigated as a promising anode material for lithium-ion batteries. The nano-porous Si/graphite composite was prepared via two-step ball-milling followed by etching process. Then carbon was incorporated by using different approaches. The nano-porous Si/graphite/C composite exhibits a reversible capacity of about 700 mAh/g with no capacity loss up to the 120th cycle at a constant current density of 0.2 mA/cm². The superior electrochemical characteristics are attributed to the nanosized pores in Si particles, which suppress the volume effect, and buffering action as well as excellent electronic and ionic conductivity of carbon materials.     

机械球磨制备Mg70Ni30基复合材料在TiF3/TiO2催化机理下的电化学性能

以TiO2及TiF3为催化剂机械球磨制备Mg70 Ni30合金.XRD分析了球磨以后的合金微观结构,用程控电池测试仪测试了合金电极的电化学贮氢性能.研究表明,随着TiO2加入量增大,合金的电化学循环稳定性得到显著增强,且合金的电化学贮氢容量进一步提高,TiF3的加入使电化学容量有很大提高.电位阶跃法计算出合金的氢扩散系...     

MgAl2O4-Spinel Synthesized by High-Energy Ball Milling and Reaction Sintering

A new way to prepare magnesia-alumina-spinel was investigated making use of a mixed powder system of MgO and metallic Al-3 wt% Mg. Intensive ball milling was applied which provides the formation of new powder particles as composite of both components in intimate contact. The new configuration of the particles had a significant impact on the reaction sintering behavior leading to single phase spinel microstructures at moderate temperatures below 1400°C. Optimized milling of the powder mixture was therefore required providing reduced crystallite sizes and strongly enlarged interfacial area shared by the reacting components. The optimal milling time was identified by the complete reaction of the starting powders to spinel during sintering. Shorter milling times led to incomplete reactions and longer milling times contaminated the milling product by debris from the milling tools. The amount of interfaces generated by the intimate mixing dominated the sintering reaction kinetics whereas the specific surfaces area was of secondary importance.