Effect of ZnO Coating on the Electrochemical Performance of LiMn1.5Ni0.5O4 Cathode Material

2006 ◽  
Vol 972 ◽  
Author(s):  
Rahul Singhal ◽  
Maharaj S Tomar ◽  
Juan G Burgos ◽  
Arun Kumar ◽  
Ram S Katiyar

AbstractLiMn1.5Ni0.5O4 cathode material was prepared by sol-gel method and annealed at 850°C for 15 hrs. The prepared powder was coated with ZnO by dissolving zinc acetate in methanol and LiMn1.5Ni0.5O4 powder was mixed in this solution followed by the continuous stirring for 4 hr. The LiMn1.5Ni0.5O4 and ZnO coated LiMn1.5Ni0.5O4 powder was characterized using X-ray diffraction, TEM and Raman spectroscopy. The coin cell was fabricated using LiMn1.5Ni0.5O4 and ZnO coated LiMn1.5Ni0.5O4 as cathode materials, LiPF6, dissolved in EC/DMC (1:1 wt ratio) as electrolyte, and Li foil as anode. The cyclic voltammetric and charge-discharge characteristics were carried out for the coin cell using LiMn1.5Ni0.5O4 and ZnO coated LiMn1.5Ni0.5O4 cathode materials. It was found that the ZnO coated LiMn1.5Ni0.5O4 cathode materials showed improved discharge capacity (∼146mAh/g) as compared to the pure LiMn1.5Ni0.5O4 (∼140mAh/g). The discharge capacity retention after 50 cycles was found to be about 94% and 97% for LiMn1.5Ni0.5O4 and ZnO coated LiMn1.5Ni0.5O4 cathode materials, respectively.

2011 ◽  
Vol 347-353 ◽  
pp. 3662-3665 ◽  
Author(s):  
Yu Hui Wang ◽  
Zhe Li ◽  
Kai Zhu ◽  
Gang Li ◽  
Ying Jin Wei ◽  
...  

The Li[Li0.2Co0.4Mn0.4]O2 cathode material was prepared by a sol-gel method. Combinative X-ray diffraction (XRD) studies showed that the material was a solid solution of LiCoO2 and Li2MnO3. The material showed a reversible discharge capacity of 155.0 mAhg−1 at -20 °C, which is smaller than that at room temperature (245.5 mAhg−1). However, the sample exhibited capacity retention of 96.3 % at -20 °C, only 74.2 % at 25 °C. The good electrochemical cycle performance at low temperature was due to the inexistence of Mn3+ in the material.


2010 ◽  
Vol 160-162 ◽  
pp. 666-670
Author(s):  
Min Zhang Zheng ◽  
Xiao Mei Liu

To obtain more detail information about the cathode of La0.7Sr0.3Cu1-xFexO3-δ(x= 0.1,0.3,0.5,0.7,0.9)in IT-SOFCs, the cathode material La0.7Sr0.3Cu1-xFexO3-δ(x=0.1, 0.3, 0.5, 0.7, 0.9)was synthesized by a sol-gel method. X-ray diffraction revealed it to be form a single phase of perovskite. The high temperature electrical conductivity was measured by using the four-point dc technique, and cathodic overpotential with SDC(Sm0.15Ce0.85O1.925) electrolyte support was measured by using a current-interruption technique. The investigation of electrocheimical properties suggested that La0.7Sr0.3Cu0.7Fe0.3O3-δ has the highest electrical conductivity and the lowest cathodic polarization. Using La0.7Sr0.3Cu0.7Fe0.3O3-δ as cathode and 65%NiO/SDC as anode based on SDC electrolyte one can obtain higher current density and power density at intermediate temperatures, La0.7Sr0.3Cu0.7Fe0.3O3-δ is considered to be a possible cathode adapted to IT-SOFCs.


2014 ◽  
Vol 687-691 ◽  
pp. 4327-4330
Author(s):  
Yan Wang ◽  
Zhe Sheng Feng ◽  
Lu Lin Wang ◽  
Jin Ju Chen ◽  
Zhen Yu He

Li0.97K0.03FePO4 and Li0.97K0.03FePO4/graphene composites were synthesized by carbothermal reduction method using acetylene black as carbon source. The structure and electrochemical properties of the prepared materials were investigated with X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, galvanostatic charge and discharge and electrochemical impedance spectra tests. The results indicated that K doping improves the cyclic stability of samples, the addition of small amounts of graphene results in better electronic properties on sample. Li0.97K0.03FePO4/graphene showed discharge capacity of 158.06 and 90.55 mAh g-1 at 0.1 C and 10 C, respectively. After the 50 cycle test at different rates, the reversible discharge capacity at 0.1 C was 158.58 mAh g-1, indicating the capacity retention ratio of 100.32%.


2012 ◽  
Vol 560-561 ◽  
pp. 860-863
Author(s):  
Fang Hu ◽  
Mo Ran Sun ◽  
Yu Sheng Wu ◽  
Chun Hua Zhang

Li1-xLaxV3O8 cathode materials has been synthesized by pechini sol-gel method. The electrochemical performances of Li1-xLaxV3O8(x=0-0.05) have been studied by X-ray diffraction (XRD), galvanostatic charge-discharge, and cyclic voltammetric (CV). The results showed that the optimal content of the La3+ doping in LiV3O8 was x=0.01, and the first discharge capacity of Li0.99La0.01V3O8 sample in the voltage range of 2.0-4.0V was 230mAhg-1, which was much higher than that of LiV3O8 (200mAhg-1). The Li0.99La0.01V3O8 cathode also showed higher discharge voltage plateau than LiV3O8 cathode from the CV curves.


2019 ◽  
Author(s):  
◽  
Khaleel Idan Hamad

Many synthesis techniques like sol-gel, co-precipitation, hydrothermal, pyrolysis, and many more have been used to synthesize batteries' active electrode materials. High surface area cathode materials with smaller nanoparticles are favored for their higher reactivity compared to materials with particles of larger size. Sol-gel and co-precipitation methods have been primarily adopted because they can produce the desirable particle size easily and on a large scale. This dissertation details an efficient and cost-effective process for using a newly developed sol-gel method that uses glycerol solvent instead of the conventionally used water. Glycerol has three hydroxyl groups (OH) instead of one in water. These can play an important role in nanoparticle formation at earlier stages by speeding up the reaction. One of the main reasons for capacity fade in batteries is cationic mixing between Ni2+ and Li+. This results in blocking of the Li+ path and ultimately poor cyclability. This capacity fade has been successfully minimized in our current work by taking advantage of the high heat released from glycerol to get partially crystalline nanoparticles that could mitigate cationic mixing at high temperatures. The first cathode material synthesized using glycerol solvent was LiMn1/3Ni1/3Co1/3O2 (LMNC) layered oxide cathode material. Temperature's effects on the particles' morphologies, sizes, and electrochemical performances have been studied at four different temperatures. LMN2 was annealed at 900 �C/8hr and shows desirable particles size of ~ 0.3 (�_m), an initial discharge capacity of 177.1 mAh/g in the first cycle, and a superior capacity retention of 83.7% after 100 cycles. The process takes eight hours, rather than >12hr when using other solvents to prepare LMNC material at high temperatures. The results also demonstrate the higher stability and lower cationic mixing after 100 cycles. To increase capacity and voltage, lithium-rich cathode materials with the formula Li1.2Mn0.51Ni0.145+xCo0.145-xO2 (x = 0 (LR2), 0.0725 (LR1)) have been successfully synthesized. In this material, cobalt (Co) content has been decreased by half and the larger produced particles have suppressed the total activation of Li2MnO3 phase in the first charge cycle. The specific discharge capacity retention of LR1 at 1C between 2 and 4.8 V was more than 100% after 100 cycles. Further improvements to LR1 cathode materials have led to an increase in the initial discharge capacity to 248 mAh/g at 0.1C. This is achieved by using an equimolecular combination of acetate and nitrate salt anions (LRACNI) with cornstarch. Cornstarch acts as a capping agent with the nitrate salt anions, and a gelling agent with acetate based anions. LRACNI shows an intermediate particle size with satisfactory capacity retention upon cycling and the lowest cationic mixing. LiNi0.8Co0.15Al0.05O2 (NCA) is one of the most commercialized cathode materials for lithium-ion batteries. It is challenging to have a high Ni content with Li in one combination electrode because cationic mixing increases proportionally. The use of glycerol has diminished the cationic mixing. High capacity retentions of 97% at 1C after 50 cycles, 87.6% at 0.3C after 100 cycles, and 93.6% at 0.1C after 70 cycles have been successfully achieved, which are better than those previously reported.


2011 ◽  
Vol 1326 ◽  
Author(s):  
Rene Fabian Cienfuegos ◽  
Leonardo Chávez Guerrero ◽  
Sugeheidy Carranza ◽  
Laurie Jouanin ◽  
Guillaume Marie ◽  
...  

ABSTRACTThe goal in this study was to synthesize a lanthanum - nickel phase (Ruddlesden-Popper phases) La4Ni3O10. This material was prepared using a polymeric route. An easy synthesis method is presented in order to obtain an economical cathode material, which can be used in Solid Oxide Fuel Cells (SOFC). The polymeric precursors were prepared following the Castillo method. The originality of this work was to optimize the ratio HMTA/ metallic salts from 1 to 6. The obtained powders were characterized by thermal analysis; Differential Scanning Calorimetry (DSC Q10 Instrument TA), Thermogravimetric Analysis (TGA - Q50 Instrument TA-) and X-ray diffractometer (Bruker, D8 Advance diffractometer), in order to determine the crystallized phase. Experiments 5 and 6 did not present coagulation but after few days, solution 5 was transformed into a gel. Gels 2 to 5 were heated in order to obtain a solid material. These powders are characterized by thermogravimetric and thermo-differential methods. The powders obtained at 800, 900 and 1000°C were analyzed by X-ray diffraction and it was found that the temperature to get to the La4Ni3O10 phase was 1000ºC.


2013 ◽  
Vol 788 ◽  
pp. 141-146
Author(s):  
Feng Wang ◽  
Huai Ying Zhou ◽  
Jiang Wang ◽  
Zhong Min Wang ◽  
Huai Gang Zhang ◽  
...  

The effect of annealing treatment on the structure and electrochemical properties of LaNi4.5Co0.25Al0.25 alloy was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurement. XRD results show that the matrix phases are still LaNi5 (hexagonal CaCu5 type structure) but the intensity peaks become sharper after heat treatment. Electrochemical experiments at 301 K indicate that annealing treatment can significantly improve the discharge capacity and cyclic stability of LaNi4.5Co0.25Al0.25 alloy at suitable treatment condition. The alloy has the best discharge capacity (324.4 mAg-1) due to its composition homogenization after heat treatment at 1373 K/8 h, while the best capacity retention is about 80.12 % because of lower expansion rate and better anti-pulverization ability after heat treatment at 1273 K/8 h.


2011 ◽  
Vol 183-185 ◽  
pp. 1553-1557 ◽  
Author(s):  
Fang Gu ◽  
Qian Nie

Preparation of LiCoO2 cathode materials from spent lithium ion batteries are presented. The processes contain reduction, separation, precipitation, regeneration. The optimum conditions of recovery are: the calcination temperature is 500°C, the volume rate of sulfuric acid and the water reaches 0.375, the hightest leach-ing rate of cobalt is 43.53%. According to the solubility of oxalate, ammonium oxalate is choiced as precipitation agent. The investigation of X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge testes at voltage ranges rate from 2.8V to 4.2V versus Li , 0.2 C rate are performed. The results reveal that the regenerative LiCoO2 is pure phase, initial discharge capacity is 128.63 mAh•g-1, after 50 cycles the discharge capacity is 118.61 mAh•g-1, capacity retention rate is 92.21%. The regenerative LiCoO2 exhibits excellent electrochemical performance and stability. The materials may find promising applications in lithium ion batteries.


2010 ◽  
Vol 1276 ◽  
Author(s):  
Rene Fabian Cienfuegos ◽  
Sugeheidy Carranza ◽  
Leonardo Chávez ◽  
Laurie Jouanin ◽  
Guillaume Marie ◽  
...  

AbstractThe goal in this study is to synthesize a Ruddleden-Poper La-Ni phase (La4Ni3O10) using a polymeric route. This material exhibits mixed ionic and electronic conduction (MIEC) properties and can be used as cathode material in the manufacture of Solid Oxide Fuel Cells (SOFC). In addition, an easy and inexpensive synthesis method is presented The polymeric precursors are prepared following the Castillo method using optimized the complexation ratios (HMTA/metallic salts) from 1 to 6. The obtained powders are characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) in order to determine the processing conditions for formation of the crystalline phase. Experiments performed using complexation ratios of 5 and 6 do not show coagulation. However, the solution prepared using a complexation ratio of 5, is transformed into a gel after few days. Gels produced from solutions prepared with complexation ratios from 2 to 5 were heated at 800, 900 and 1000°C to obtain solid materials. These powders are characterized by TGS, DSC and XRD and it is found that the temperature needed to obtain crystalline La4Ni3O10 was 1000°C.


2016 ◽  
Vol 852 ◽  
pp. 908-915
Author(s):  
Yu Feng Song ◽  
Ying Ying Liu ◽  
Lei Lei Cui ◽  
Xiao Wei Miao ◽  
Hong Bin Zhao ◽  
...  

Li-rich layer-structure 0.6Li2MnO3·0.4LiNi1/3Co1/3Mn1/3O2 (LMO) cathode materials have been synthesized by sol-gel method using citric acid as a cheating agent. The effects of different ratios of solvent and the amount of excessive lithium are discussed systematically. When changing the ratio of ethanol/H2O and the amount of excessive lithium, the morphology and electrochemical properties will be changed accordingly. The crystal structure of Li-rich LMO was characterized by X-ray diffraction. The morphology was characterized by scanning electron microscope, and the Li-rich LMO cathodes show bulk with the particle size of around 150 nm. The charge/discharge test showed the Li-rich LMO synthesized with 100% ethanol and 5% Li excess sintered at 900 °C for 24 h subsequently has the best electrochemical performance. Within the cut-off voltage between 2.5 and 4.8 V, the initial discharge capacity is 256.8 mAh g-1 at 0.1 C; and after 50 cycles the discharge capacity remains 230.2 mAh g-1. By modifying the ratio of solvent in the formation of gel, it is promising to extend the synthesis of other electrode materials of lithium ion batteries basing on the traditional sol-gel method.


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