scholarly journals Enhanced Electrochemical Performance of LiNi0.5Mn1.5O4 Composite Cathodes for Lithium-Ion Batteries by Selective Doping of K+/Cl− and K+/F−

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2323
Author(s):  
Aijia Wei ◽  
Jinping Mu ◽  
Rui He ◽  
Xue Bai ◽  
Xiaohui Li ◽  
...  
Keyword(s):  
Rate Capability ◽  
Lithium Ion ◽  
High Energy ◽  
Electrochemical Kinetics ◽  
Doping Amount ◽  
Solid State Method ◽  
Teller Distortion ◽  
Co Doping ◽  
Composite Cathodes ◽  
Co Doped

K+/Cl− and K+/F− co-doped LiNi0.5Mn1.5O4 (LNMO) materials were successfully synthesized via a solid-state method. Structural characterization revealed that both K+/Cl− and K+/F− co-doping reduced the LixNi1−xO impurities and enlarged the lattice parameters compared to those of pure LNMO. Besides this, the K+/F− co-doping decreased the Mn3+ ion content, which could inhibit the Jahn–Teller distortion and was beneficial to the cycling performance. Furthermore, both the K+/Cl− and the K+/F− co-doping reduced the particle size and made the particles more uniform. The K+/Cl− co-doped particles possessed a similar octahedral structure to that of pure LNMO. In contrast, as the K+/F− co-doping amount increased, the crystal structure became a truncated octahedral shape. The Li+ diffusion coefficient calculated from the CV tests showed that both K+/Cl− and K+/F− co-doping facilitated Li+ diffusion in the LNMO. The impedance tests showed that the charge transfer resistances were reduced by the co-doping. These results indicated that both the K+/Cl− and the K+/F− co-doping stabilized the crystal structures, facilitated Li+ diffusion, modified the particle morphologies, and increased the electrochemical kinetics. Benefiting from the unique advantages of the co-doping, the K+/Cl− and K+/F− co-doped samples exhibited improved rate and cycling performances. The K+/Cl− co-doped Li0.97K0.03Ni0.5Mn1.5O3.97Cl0.03 (LNMO-KCl0.03) exhibited the best rate capability with discharge capacities of 116.1, 109.3, and 93.9 mAh g−1 at high C-rates of 5C, 7C, and 10C, respectively. Moreover, the K+/F− co-doped Li0.98K0.02Ni0.5Mn1.5O3.98F0.02 (LNMO-KF0.02) delivered excellent cycling stability, maintaining 85.8% of its initial discharge capacity after circulation for 500 cycles at 5C. Therefore, the K+/Cl− or K+/F− co-doping strategy proposed herein will play a significant role in the further construction of other high-voltage cathodes for high-energy LIBs.

Effects of Na and V Co-Doping on Electrochemical Performance of LiFePO4/C

2013 ◽  
Vol 724-725 ◽  
pp. 1067-1070
Author(s):  
Ning Yu Gu ◽  
Yang Li ◽  
Chao Li
Keyword(s):  
Solid State ◽  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Cathode Materials ◽  
Lithium Ion ◽  
Electrochemical Performances ◽  
Solid State Method ◽  
Co Doping ◽  
State Method ◽  
Co Doped

To enhance the electrochemical performance of LiFePO4/C, Na and V have been co-doped in cathode material of the lithium ion batteries. A series of Na and V doped samples Li0.97Na0.03Fe(1-x)VxPO4/C (x=0, 0.01, 0.03, 0.05) cathode materials are synthesized by solid state method. Results show that the Li0.97Na0.03Fe0.97V0.03PO4/C exhibited the best electrochemical performances.

scholarly journals Structure, Defects and Microwave Dielectric Properties of Al-doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

2021 ◽  
Author(s):  
Weijia Guo ◽  
Zhiyu Ma ◽  
Yu Luo ◽  
Yugu Chen ◽  
Zhenxing Yue ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Relative Dielectric Constant ◽  
Doping Amount ◽  
Solid State Method ◽  
Depolarization Current ◽  
Structure Defects ◽  
Microwave Dielectric ◽  
Co Doped

Abstract Ba4Nd9.33Ti18-zAl4z/3O54 (BNT-A, 0 ≤ z ≤ 2) and Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) ceramics were prepared by solid state method, and the effects of the two doping methods on microwave dielectric properties were compared. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) values of the ceramics decreased, and the quality factor (Q, usually expressed by Q×f, where f is the resonant frequency) of the ceramics obviously increased when z ≤ 1.5. With the same z value, the εr and Q×f values of Al/Nd co-doped ceramics are both higher than those of Al-doped ceramics. Rietveld refinement, Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were applied to clarify the relationship among the structure, defects and microwave dielectric properties. It is shown that the Q×f values of those ceramics were closely related to the strength of the A-site cation vibration and the concentration of oxygen vacancies (B). Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25.

Preparation and Characterization of High-Voltage Cathode Material LiNi0.5Mn1.5O4 for Lithium Ion Batteries

2019 ◽  
Vol 953 ◽  
pp. 121-126
Author(s):  
Zhe Chen ◽  
Quan Fang Chen ◽  
Sha Ne Zhang ◽  
Guo Dong Xu ◽  
Mao You Lin ◽  
...  
Keyword(s):  
Cathode Material ◽  
Lithium Ion Batteries ◽  
Cathode Materials ◽  
Synthesis Method ◽  
Rate Capability ◽  
Lithium Ion ◽  
Diffusion Path ◽  
High Energy ◽  
High Energy Density ◽  
Charge Discharge

High energy density and rechargeable lithium ion batteries are attracting widely interest in renewable energy fields. The preparation of the high performance materials for electrodes has been regarded as the most challenging and innovative aspect. By utilizing a facile combustion synthesis method, pure nanostructure LiNi0.5Mn1.5O4 cathode material for lithium ion batteries were successfully fabricated. The crystal phase of the samples were characterized by X-Ray Diffraction, and micro-morphology as well as electrochemistry properties were also evaluated using FE-SEM, electrochemical charge-discharge test. The result shows the fabricated LiNi0.5Mn1.5O4 cathode materials had outstanding crystallinity and near-spherical morphologies. That obtained LiNi0.5Mn1.5O4 samples delivered an initial discharge capacity of 137.2 mAhg-1 at the 0.1 C together with excellent cycling stability and rate capability as positive electrodes in a lithium cell. The superior electrochemical performance of the as-prepared samples are owing to nanostructure particles possessing the shorter diffusion path for Li+ transport, and the nanostructure lead to large contact area to effectively improve the charge/discharge properties and the rate property. It is demonstrated that the as-prepared nanostructure LiNi0.5Mn1.5O4 samples have potential as cathode materials of lithium-ion battery for future new energy vehicles.

scholarly journals Cathode porosity is a missing key parameter to optimize lithium-sulfur battery energy density

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ning Kang ◽  
Yuxiao Lin ◽  
Li Yang ◽  
Dongping Lu ◽  
Jie Xiao ◽  
...  
Keyword(s):  
Energy Density ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
Reversible Capacity ◽  
High Energy ◽  
Carbon Composite ◽  
Composite Cathodes ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur ◽  
Key Parameter

Abstract While high sulfur loading has been pursued as a key parameter to build realistic high-energy lithium-sulfur batteries, less attention has been paid to the cathode porosity, which is much higher in sulfur/carbon composite cathodes than in traditional lithium-ion battery electrodes. For high-energy lithium-sulfur batteries, a dense electrode with low porosity is desired to minimize electrolyte intake, parasitic weight, and cost. Here we report the profound impact on the discharge polarization, reversible capacity, and cell cycling life of lithium-sulfur batteries by decreasing cathode porosities from 70 to 40%. According to the developed mechanism-based analytical model, we demonstrate that sulfur utilization is limited by the solubility of lithium-polysulfides and further conversion from lithium-polysulfides to Li2S is limited by the electronically accessible surface area of the carbon matrix. Finally, we predict an optimized cathode porosity to maximize the cell level volumetric energy density without sacrificing the sulfur utilization.

scholarly journals Recent Advances in Nanostructured Transition Metal Carbide- and Nitride-Based Cathode Electrocatalysts for Li–O2 Batteries (LOBs): A Brief Review

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2106
Author(s):  
K. Karuppasamy ◽  
K. Prasanna ◽  
Vasanth Rajendiran Jothi ◽  
Dhanasekaran Vikraman ◽  
Sajjad Hussain ◽  
...  
Keyword(s):  
Transition Metal ◽  
Rational Design ◽  
Rate Capability ◽  
High Energy ◽  
High Energy Density ◽  
Electrochemical Kinetics ◽  
Transition Metal Carbide ◽  
Round Trip ◽  
Slow Kinetics ◽  
Kinetics Of

A large volume of research on lithium–oxygen (Li–O2) batteries (LOBs) has been conducted in the recent decades, inspired by their high energy density and power density. However, these future generation energy-storage devices are still subject to technical limitations, including a squat round-trip efficiency and a deprived rate-capability, due to the slow-moving electrochemical kinetics of both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) over the surface of the cathode catalyst. Because the electrochemistry of LOBs is rather complex, only a limited range of cathode catalysts has been employed in the past. To understand the catalytic mechanisms involved and improve overall cell performance, the development of new cathode electrocatalysts with enhanced round-trip efficiency is extremely important. In this context, transition metal carbides and nitrides (TMCs and TMNs, respectively) have been explored as potential catalysts to overcome the slow kinetics of electrochemical reactions. To provide an accessible and up-to-date summary for the research community, the present paper reviews the recent advancements of TMCs and TMNs and its applications as active electrocatalysts for LOBs. In particular, significant studies on the rational design of catalysts and the properties of TMC/TMN in LOBs are discussed, and the prospects and challenges facing the continued development of TMC/TMN electrocatalysts and strategies for attaining higher OER/ORR activity in LOBs are presented.

scholarly journals Enhanced Cycling Stability of LiCuxMn1.95−xSi0.05O4 Cathode Material Obtained by Solid-State Method

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1302 ◽  
Author(s):  
Hongyuan Zhao ◽  
Fang Li ◽  
Xiuzhi Bai ◽  
Tingting Wu ◽  
Zhankui Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Copper Ions ◽  
Cycling Performance ◽  
Cycling Stability ◽  
Doping Amount ◽  
Solid State Method ◽  
Electrochemical Tests ◽  
Improvement Effect ◽  
State Method ◽  
Co Doped

The LiCuxMn1.95−xSi0.05O4 (x = 0, 0.02, 0.05, 0.08) samples have been obtained by a simple solid-state method. XRD and SEM characterization results indicate that the Cu-Si co-doped spinels retain the inherent structure of LiMn2O4 and possess uniform particle size distribution. Electrochemical tests show that the optimal Cu-doping amount produces an obvious improvement effect on the cycling stability of LiMn1.95Si0.05O4. When cycled at 0.5 C, the optimal LiCu0.05Mn1.90Si0.05O4 sample exhibits an initial capacity of 127.3 mAh g−1 with excellent retention of 95.7% after 200 cycles. Moreover, when the cycling rate climbs to 10 C, the LiCu0.05Mn1.90Si0.05O4 sample exhibits 82.3 mAh g−1 with satisfactory cycling performance. In particular, when cycled at 55 °C, this co-doped sample can show an outstanding retention of 94.0% after 100 cycles, whiles the LiMn1.95Si0.05O4 only exhibits low retention of 79.1%. Such impressive performance shows that the addition of copper ions in the Si-doped spinel effectively remedy the shortcomings of the single Si-doping strategy and the Cu-Si co-doped spinel can show excellent cycling stability.

Fast lithium-ion storage of Nb2O5 nanocrystals in situ grown on carbon nanotubes for high-performance asymmetric supercapacitors

RSC Advances ◽  
2015 ◽  
Vol 5 (51) ◽  
pp. 41179-41185 ◽  
Author(s):  
Xiaolei Wang ◽  
Ge Li ◽  
Ricky Tjandra ◽  
Xingye Fan ◽  
Xingcheng Xiao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Performance ◽  
Rate Capability ◽  
Lithium Ion ◽  
High Energy ◽  
Asymmetric Supercapacitors ◽  
Ion Storage ◽  
Energy And Power Density

Nanocomposites of Nb2O5 NCs in situ grown on CNTs are successfully developed with excellent rate capability, leading to the successful fabrication of asymmetric supercapacitors with high energy and power density and long-term cycling stability.

Sulfur–nitrogen co-doped porous carbon nanosheets to control lithium growth for a stable lithium metal anode

2019 ◽  
Vol 7 (31) ◽  
pp. 18267-18274 ◽  
Author(s):  
Mei Chen ◽  
Jianhui Zheng ◽  
Ouwei Sheng ◽  
Chengbin Jin ◽  
Huadong Yuan ◽  
...  
Keyword(s):  
Porous Carbon ◽  
High Capacity ◽  
Rate Capability ◽  
Lithium Metal ◽  
Capacity Retention ◽  
Carbon Nanosheets ◽  
Metal Anode ◽  
Co Doping ◽  
Lithium Metal Anode ◽  
Co Doped

Based on S, N co-doping, a full cell exhibits high capacity retention and excellent rate capability.

Optimizing Performance of Li4Ti5O12 (LTO) by Addition of Sn Microparticle in High Loading as Anode for Lithium-Ion Batteries

2020 ◽  
Vol 1000 ◽  
pp. 20-30
Author(s):  
Bambang Priyono ◽  
Reza Miftahul Ulum ◽  
Anne Zulfia Syahrial ◽  
Stefanie Trixie ◽  
Heri Jodi ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Lithium Ion Batteries ◽  
Surface Area ◽  
Electrochemical Impedance ◽  
Lithium Ion ◽  
High Energy ◽  
Solid State Method ◽  
High Energy Ball Mill ◽  
Before And After ◽  
Two Peaks

Li4Ti5O12/Sn was successfully synthesized by a solid-state method using the High Energy Ball Mill Machine as anode for Lithium-Ion batteries. The addition of various (10%, 20%, 30%) Sn-micro particle is aimed to enhance LTO's conductivity and capacity. Characterization of the sample's structure was performed using X-ray diffraction (XRD), which expose the presence of TiO2 rutile and Sn in each sample. The surface area of samples observed using Brunner-Emmet-Teller (BET), which indicates the different surface area of each Sn addition. Scanning electron microscopy (SEM) suggested agglomeration and poor distribution appear in every sample. Cyclic voltammetry (CV) was performed to measure the battery's performance. Two peaks occur as a sign of reversible reaction. The impedance of Li4Ti5O12/Sn measured using electrochemical impedance spectroscopy (EIS), the test performed before and after Cyclic voltammetry (CV), each test showed the different result for each sample. Other than EIS and CV, Charge-Discharge (CD) also performed, examinations in different C-rate were performed, and higher Sn concentration leads to lower stability in high C. The result reveals that the addition of 20% Sn optimizes Li4Ti5O12 in enhancing capacity and conductivity.

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