α-Ni(OH)_2稳定性的研究

为了得到稳定化的α-Ni(OH) 2 ,使用X衍射法对添加Al或Co的α-Ni(OH) 2 的化学稳定性和电化学稳定性进行了研究 .实验表明 ,α-Ni(OH) 2 中Al,Co摩尔百分含量为 1 5 %时 ,晶型不稳定 .含Co 2 0 %的α-Ni(OH) 2 化学稳定性可达 3个月 ;含Al2 0 %的α-Ni(OH) 2 具有较好的化学稳定性和电化学稳定性 .在 7M的KOH中最少可稳定 6个月 ,充放电 1 0 0次晶型不改变 ,并且容量稳定 .     

Comparative study on microstructure of β-Ni(OH)_2 as cathode material for Ni-MH battery

β-Ni(OH)2 is the cathode active material in Ni-Cd and Ni-MH batteries. Recent inves- tigation has shown that the shape of β-Ni(OH)2 crystallite is a cylinder of D in diameter, with base plane parallel to (001) and height H in direction [001]. There are 10% ofdeformation faults and 8% of growth faults[1] in the crystallites. When the total probabil- ity of the stacking faults exceeds 15%[2], the material has the optimized electrochemical performance. As for crystallite shapes of β-Ni(O…     

Cl-和Al3+复合掺杂α-Ni(OH)2的电化学性能

采用化学反应共沉淀法制备出Cl-和Al3 阴阳离子复合掺杂的α-Ni(OH)2粉体材料。对其进行了微结构表征分析和电化学性能测试,结果表明:样品材料具有较多的微结构缺陷,用作MH-Ni电池的正极活性材料时,在充放电过程中电化学阻抗较小、质子迁移能力强。电池在以80 mA/g恒电流充电5 h,40 mA/g恒电流放电,终止电压为1.0 V的充放电制度下,其放电比容量达344.3 mAh/g,且放电工作电压稳定,循环可逆性较好,表现出较高的电化学活性。     

稳定化α—Ni（OH）2电化学性能的研究

为了得到比能量高,晶型稳定的α-Ni(OH)2,使用恒流放电方法,研究了添加剂Al,Co对α-Ni(OH)2电化学性能的影响,实验表明,添加Al的α－Ni(OH)2比容量高于β－Ni(OH)2的理论比容量,Al,Co的添加对αNi(OH)2的比容量和放电电压有影响,Al含量的增加提高了α－Ni(OH)的放电电压,Al含量为20％的α－Ni(OH)2的比容最高。     

α—Ni（OH）2稳定性的研究

为了得到稳定化α－Ni(OH)2,使用X衍射法对添加Al或Co的α－Ni(OH)2的化学稳定性和电化学稳定性进行了研究。实验表明,α－Ni(OH)2中Al,Co摩尔百分含量为15％时,晶型不稳定,含Co20％的α－Ni(OH)2化学稳定性可达3个月;含Al20％的α－Ni(OH)2具有较好的化学稳定性和电化学稳定性,在7M的KOH中最少可稳定6个月,充放电100次晶型不改变,并且容量稳定。     

稳定化α-Ni(OH)_2电化学性能的研究

为了得到比能量高、晶型稳定的α—Ni(OH ) 2 ,使用恒流放电方法 ,研究了添加剂Al,Co对α—Ni(OH) 2 电化学性能的影响 .实验表明 ,添加Al的α—Ni(OH) 2 比容量高于 β Ni(OH) 2 的理论比容量 .Al,Co的添加对α—Ni(OH) 2 的比容量和放电电压有影响 .Al含量的增加提高了α—Ni(OH)的放电电压 .Al含量为2 0 %的α -Ni(OH) 2 比容量最高     

α-Ni（OH）2／GO原位复合材料的制备及电化学性能

采用均相沉淀法分别制备了α-Ni（ OH）2和α-Ni（ OH）2/GO复合材料,并对其微观结构和电化学性能进行了考察。 XRD分析表明α-Ni（OH）2/GO 复合材料层间距更大; FT -IR 表明α-Ni（OH）2/GO复合材料中NO3-振动吸收峰峰形逐渐宽化、强度减弱; FESEM图像表明α-Ni（OH）2/GO复合材料结构更加致密。采用CV、 EIS和充放电测试表征了合成样品的电化学性能,发现α-Ni（OH）2/GO复合材料具有相对较低的阻抗、较好的循环稳定性和较高的放电比容量。     

镍空位缺陷对Ni(OH)2表面活性的影响

采用基于密度泛函理论的第一性原理方法研究了镍空位缺陷对Ni(OH)_2的表面活性的影响。通过理论模拟Ni(OH)_2最高活性表面和最易得到表面(实验最易得到表面),并以Ni(OH)_2(001)为例,讨论了表面缺陷和镍空位对表面性质的影响。研究表明:表面缺陷带来了更多的活性位点,使整个Ni(OH)_2表面体系电子变得更加活泼,电子传输性能增加,体系由半导体相向金属相转变。尿素在镍缺陷Ni(OH)_2(001)表面的吸附结果表明:Ni(OH)_2(001)与尿素存在较强的相互作用,有利于二者的进一步反应。理论研究可为实验合成高活性Ni(OH)_2催化剂提供理论依据。     

Al^（3＋）掺杂α-Ni（OH）2复合CNTs电极材料的高温性能

采用化学共沉淀法制备Al^（3＋）掺杂α-Ni（OH）2粉体,将其复合碳纳米管（CNTs）制成镍电极材料并研究其在高温下的电化学性能。结果表明：以混合CNTs（w=0.5%）的Al掺杂α-Ni（OH）2样品材料为活性物质制成镍电极,由其组装的MH-Ni电池在65℃高温环境下,采用0.2和1.0 C充放电制度的放电比容量分别为391.1和366.4 mAh·g^-1;经40次充放电循环,放电比容量衰减率分别为6.8%、11.98%,表现出较好的高温环境电化学性能。     

Structural characteristics of spherical Ni（OH）2 and its charge／discharge process mechanism

Spherical Ni(OH)2 particles were prepared by an aqueous solution precipitation route. The structure of spherical Ni(OH)2 was investigated by scanning electron microscopy and transmission electron microscopy and compared with that of traditional Ni(OH)2. The results show that the spherical nickel hydroxide consists of Ni(OH)2 spheres with a reticulate structure of platelet-like, which is almost arranged radially and the crystalline grains intervene and connect with each other to form a three-dimensional net. The spherical Ni(OH)2 particle is full of pores,crannies between cleave planes. It is supposed that this structure is beneficial to the structural stability for the spherical particles during the charge/discharge processes and can improve the cycle life of the electrode; the pores and the crannies in spherical particles can shorten the proton diffusion distance and speed its velocity, which may result in that the local polarization is lowered. The electrochemical performances of the spherical Ni(OH)2 are improved by enhancing the conducting properties of the crystalline lattice due to its quick proton diffusion.     

Ni0.5Co0.2Mn0.3(OH)2启釜工艺研究

为获得质量合格的Ni_(0.5)Co_(0.2)Mn_(0.3)(OH)_2产品,以络合共沉淀方法制备了Ni_(0.5)Co_(0.2)Mn_(0.3)(OH)_2,考察了加碱量、加氨量、加水量对前期启釜,以及后续络合共沉淀稳定性的影响。结果表明,过高或者过低的加碱量、加氨量和加水量都不利于启釜以及络合共沉淀稳定性过程控制;加碱量控制在使启釜底液pH值为11～12,加氨量控制在使启釜底液中氨质量浓度为1 500～2 000μg/mL,加水量与反应釜体积比值为0.4～0.5,在该条件下可以合成反应周期适中、性能较高的Ni_(0.5)Co_(0.2)Mn_(0.3)(OH)_2产品。     

Y（Ⅲ）和Co（Ⅱ）复合掺杂非晶态Ni（OH）2材料的电化学性能

采用微乳液快速冷冻共沉淀法制备出Y（Ⅲ）和Co（Ⅱ）复合掺杂非晶态Ni（OH）。电极活性粉体材料样品。采用XRD、SAED、SEM、EDS和Raman光谱对其结构形貌和成分进行表征分析,同时将样品组装成碱性MH-Ni电池,进行了电化学性能测试。结果发现,Y（Ⅲ）和Co（Ⅱ）复合掺杂非晶态Ni（OH）2样品材料内部微结构缺陷较多,无序性强,作为活性物质合成镍电极材料,其在电极反应过程中电荷转移电阻较低,导电能力增强,其样品电极以80mA·g^-1恒流充电6h,40mA·g^-1恒流放电,终止电压为1．0V的充放电制度下,放电平台电压为1．278V,放电容量高达335．7mAh·g^-1。     

Electrochemical performance of LiFePO4/（C＋Fe2P） composite cathode material synthesized by sol-gel method

A LiFePO4/(C+Fe2P) composite cathode material was prepared by a sol-gel method using Fe(NO3)3·9H2O,LiAc·H2O,NH4H2PO4 and citric acid as raw materials,and the physical properties and electrochemical performance of the composite cathode material were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and electrochemical tests.The Fe2P content,morphology and electrochemical performance of LiFePO4/(C+Fe2P) composite depend on the calcination tempera...     

SiO2/P（MMA-S）纳米复合电解质的制备与性能分析

聚合物锂离子电池具有安全、使用方便等特点,是当今最重要的新能源材料之一,研究和开发新型聚合物电解质是聚合物电池的核心内容。以聚甲基丙烯酸甲酯(PMMA)为聚合物基体,通过与苯乙烯(St)、三甲基丙烷三丙烯酸酯(TMPTA)进行交联共聚改性,复合有机锂盐改性纳米Si O2,通过相转化法制备多孔复合聚合物电解质膜。通过红外光谱(FT-IR)、X射线衍射(XRD)对复合聚合物膜结构进行了表征,采用扫描电镜(SEM)对该复合聚合物膜的孔形态进行了观察,采用热失重分析(TG)和差示扫描量热法(DSC)考察了复合聚合物膜热学性能,制备了结构可控、热稳定好的Si O2/P(MMA-S)纳米复合电解质。电化学研究表明:含有6%的改性纳米Si O2的电化学窗口达5.48 V,在0.1 C和0.2 C的倍率下,首次放电容量可达156.8 m Ah·g-1和147.6 m Ah·g-1,经过30次循环测试,容量保持率在93.5%和91.4%。更多还原     

Thermal Decomposition of Leightonite,K2Ca2Cu（SO4）4·2H2O

The thermal decomposition of Leightonite, K2Ca2Cu（SO4）4·2H2O, was studied by thermal gravimetric analysis（TGA）, differential thermal analysis（DTA）, X-ray diffraction（XRD）, etc. The results show that the Leightonite is dehydrated around 170 ℃ to 390 ℃ and transformed to be new intermediate （K-Cu-SO4） sulphate salt with bright-green color. Moreover, the chemical structure changes during the thernal decomposition process was describled in detail. And the as-resulting phases are demonstrated to be K2Ca2（SO4）3, K2SO4, CaSO4 ,and Cu2O.     

Excellent supercapacitive performance of a reduced graphene oxide/Ni（OH）2 composite synthesized by a facile hydrothermal route

A reduced graphene oxide/Ni（OH）2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni（OH）2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.