scholarly journals Enhanced Electrochemical Performance of Li1.27Cr0.2Mn0.53O2 Layered Cathode Materials via a Nanomilling-Assisted Solid-state Process

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 468 ◽  
Author(s):  
Chengkang Chang ◽  
Jian Dong ◽  
Li Guan ◽  
Dongyun Zhang
Keyword(s):  
Solid State ◽  
Cathode Material ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Electrochemical Process ◽  
Ion Diffusion ◽  
X Ray ◽  
State Process ◽  
Redox Pair ◽  
Electron Process

Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2 structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+ redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh·g−1 at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 × 10−10·cm2·s−1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries.

scholarly journals Operando hard X-ray photoelectron spectroscopy of LiCoO2 thin film in an all-solid-state lithium ion battery

2020 ◽  
Vol 118 ◽  
pp. 106790
Author(s):  
Hisao Kiuchi ◽  
Kazuhiro Hikima ◽  
Keisuke Shimizu ◽  
Ryoji Kanno ◽  
Fukunaga Toshiharu ◽  
...  
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Lithium Ion Battery ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
X Ray

Preparation and Effect of (3-aminopropyl)triethoxysilane-Coated LiNi0.5Co0.2Mn0.3O2 Cathode Material for Lithium Ion Batteries

2020 ◽  
Vol 20 (6) ◽  
pp. 3460-3465
Author(s):  
Mi-Ra Shin ◽  
Seon-Jin Lee ◽  
Seong-Jae Kim ◽  
Tae-Whan Hong
Keyword(s):  
Cathode Material ◽  
Lithium Ion Batteries ◽  
Cathode Materials ◽  
Photoelectron Spectroscopy ◽  
Coating Layer ◽  
Lithium Ion ◽  
X Ray ◽  
Amine Groups ◽  
Coating Layers ◽  
Discharge Capacities

Surface coating using (3-aminopropyl)triethoxysilane (APTES) has been applied to improve the electrochemical properties of LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials. The APTES coating layer on the surface of NCM523 protects the direct contact area between the cathode material and the electrolyte, and facilitates the presence of electrons through the abundance of electron-rich amine groups, thereby improving electrochemical performance. X-ray photoelectron spectroscopy confirmed the existence of APTES coating layers on the surface of NCM523 cathode materials, revealing three peaks—N1s, O1s, and Si1s—that were not identified in bare NCM523. In addition, the discharge capacities of the bare electrode and the APTES-coated NCM523 electrode were 121.06 mAh/g and 156.43 mAh/g, respectively. To the best of our knowledge, the use of an APTES coating on NCM523 cathode materials for lithium-ion batteries has never been reported.

Effect of Sintering on Structural Modification and Phase Transition of Al-Substituted LLZO Electrolytes for Solid State Battery Applications

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
K. Ganesh Kumar ◽  
P. Balaji Bhargav ◽  
C. Balaji ◽  
Ahmed Nafis ◽  
K. Aravinth ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid Electrolyte ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Impedance Analysis ◽  
Chemical Compositions ◽  
X Ray ◽  
Reitveld Refinement ◽  
Solid State Battery

Abstract Owing to high lithium ion conductivity and good stability with lithium metal, Li7La3Zr2O12 (LLZO—a solid electrolyte) has emerged as a viable candidate for solid-state battery applications. In the current study, Al-substituted LLZO (Al-LLZO) powder is synthesized using a typical solid-state reaction. The pellets are made with the synthesized powder and are subjected to annealing for different durations and its effect on the structural properties of the Al-LLZO is investigated in detail. Reitveld refinement of the powder X-ray diffraction pattern reveals that the sintered Al-LLZO belong to the cubic system with the Ia-3d space group at room temperature. Morphology and microstructural properties of sintered powder are analyzed using field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM)/selected area electron diffraction (SAED), respectively. The FESEM image of LLZO pellets shows well-structured cubic grains spread evenly over on the surface after sintering. The chemical compositions of the sample are identified using energy dispersive X-ray analysis (EDAX). The surface chemistry of the prepared samples is examined by X-ray photoelectron spectroscopy (XPS), which states that the observed photoelectron signals from O 1s at about 531 eV and Li1s at 54.52 eV correspond to the Li-O bond in Al-LLZO. Raman spectra have been analyzed and the observed Raman peaks appearing at 299 cm−1, 393 cm−1, 492 cm−1, and 514 cm−1 were assigned to Eg, F2g, A1g, and F2g, respectively. Phase transformation from C-LLZO to the pyrochore LZO phase is noticed when the sample is sintered for 12 h at 1100 °C. The impedance analysis is carried out to measure the conductivity of the Al-LLZO pellet and is found to be 0.3 × 10−5 S cm−1, which is suitable for solid electrolyte applications in lithium ion batteries.

Synthesis and Characterization of LiVOPO4 Cathode Material by Solid-State Method

2012 ◽  
Vol 554-556 ◽  
pp. 436-439 ◽  
Author(s):  
An Ping Tang ◽  
Ze Qiang He ◽  
Jie Shen ◽  
Guo Rong Xu
Keyword(s):  
Solid State ◽  
Cathode Material ◽  
Lithium Ion ◽  
Chemical Diffusion ◽  
Chemical Diffusion Coefficient ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
State Method

Lithium vanadyl phosphate (β-LiVOPO4) cathode material for lithium ion batteries was prepared via a novel solid state method. The microstructure and electrochemical properties of the sample were characterized by X-ray diffraction, scanning electron microscopy, galvanostatically discharge/discharge and cyclic voltammetry techniques, respectively. X-ray diffraction patterns showed that β-LiVOPO4 has an orthorhombic structure with space group of Pnma. The discharge capacity of LiVOPO4 sample is 89.9 mAh•g-1 in the first cycle, and in the 50th cycle it is 76.2 mAh•g-1 at the current density of 10 mA•g-1 between 3.0-4.5 V. The chemical diffusion coefficient ( ) value determined from CV is about 10-11 cm2 s-1. Experimental results indicate that further efforts are needed to improve electrochemical performances of LiVOPO4 material synthesized by solid state method; however, it has a higher discharge plateau around 3.9 V.

Synthesis and Characterization of Carbon-Coated LiFePO4 with Various Carbon Sources as Cathode Material for Lithium Ion Batteries through a Solid-State Process

2015 ◽  
Vol 827 ◽  
pp. 186-191
Author(s):  
Joko Triwibowo ◽  
Irvan Alamsyah ◽  
Jan Setiawan
Keyword(s):  
Solid State ◽  
Cathode Material ◽  
Electrochemical Impedance ◽  
Carbon Sources ◽  
Lithium Ion ◽  
Liquid Form ◽  
Nitrogen Gas ◽  
State Process ◽  
Bet Analysis ◽  
Carbon Coated

Synthesis of carbon-coated LiFePO4 as cathode material is performed through a solid-state process. Materials in the form of a powder comprising LiOH.H2O and Fe2O3 and H3PO4 in liquid form are mixed evenly to obtain a homogeneous powder. Through the drying process in an oven with a temperature of 80°C for 24 hours a dry powder is obtained. Powder is subsequently ground and calcined in the horizontal tube furnace at a temperature of 320°C for 10 hours under the flowing nitrogen gas. The obtained powder is further ground and mixed with carbon sources as much as 4wt% of the total powder. Citric acid, tartaric acid and fructose are used as the carbon source. These homogeneously mixed powders are subsequently sintered at a temperature of 800°C for 8 hours under the flowing nitrogen gas. Phase obtained from the solid-state process was analyzed by XRD. Phase composition is analyzed by Rietveld refinement that is included in the GSAS-program. The conductivity of obtained powder as cathode materials is tested by EIS (Electrochemical Impedance Spectroscopy). SEM and BET analysis tests are conducted to determine the morphology of powder which can influence the conductivity of the material.

Enhancing the Li+ diffusion in Li3VO4by coupling withreduced graphene oxide for lithium-ion batteries

2021 ◽  
Vol 17 ◽  
Author(s):  
Mingxuan Guo ◽  
Haibo Li
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Ion Diffusion ◽  
X Ray ◽  
Host Materials

Background: Owing to the excellent theoretical specific capacity and safety intercalation potential, Li3VO4¬ (LVO) has been proposed as anadvanced anode material for lithium ions batteries (LIBs). However, the LVO suffers from low electronic conductivity that limits its commercialization. Objective: The reduced graphene oxide (rGO) is recommended to couple with micro-LVO particles aiming to enhance the conductivity of compositeelectrodes. Method: The LVO@rGO compositeis synthesized by a facile hydrothermal method. The morphology, crystallinity, valance state and electrochemical behavior of LVO@rGO are characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical workstation, respectively. Further, the LIBs’ performance is explored by making a coins-type half-cell LIBs battery via battery system. Results: The Li+ diffusion rate of the optimized LVO@rGO electrode is 7.67×10-23 cm2 s-1, which improves two orders of magnitudesof pure LVO electrode. As a result, the LVO@rGO anode delivers a reversible capacity of 190.1 mAh/g at 0.1 A/g after 100 cycles, which is even twice higher than that of pure LVO anode (90.6 mAh/g). Besides,it exhibitssuperior rate capability, i.e.a reversible capability of 285.0, 220.2, 158.7, 105.2 and 71.7 mAh/g at 0.05, 0.1, 0.2, 0.5 and 1.0 A/g, respectively. Conclusion: The high conductivity and flexible texture enable rGO an idea building block to enhance the Li ion diffusion of whole electrode. On the other hand, it is instrumental in alleviating the aggregation of host materials, leading to high specific surface and specific capacity.

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