scholarly journals Variation of carbon coatings on the electrochemical performance of LiFePO4 cathodes for lithium ionic batteries

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44296-44302 ◽  
Author(s):  
Weiwei Jiang ◽  
Mengqiang Wu ◽  
Fei Liu ◽  
Jian Yang ◽  
Tingting Feng

Asphalt-derived and glucose-derived carbon proved to be soft carbon-coating (SCC) and hard carbon-coating (HCC), and it was found that LFP/SCC showed a superior performance in capacity and rate capability than that of LFP/HCC.

2016 ◽  
Vol 40 (12) ◽  
pp. 9986-9992 ◽  
Author(s):  
Xin-Yi Zhao ◽  
Xue Bai ◽  
Wei Yang ◽  
Dong Shen ◽  
Huan Yang ◽  
...  

MnO nanoparticles coated with pitch-derived soft carbon exhibit greatly enhanced electrochemical performance compared to those coated with glucose-derived hard carbon.


2018 ◽  
Vol 21 (2) ◽  
pp. 071-075 ◽  
Author(s):  
Ji-Woong Shin ◽  
Jong-Tae Son

Using LiNi0.8Co0.1Mn0.1O2 as a starting material, a surface-modified cathode material was obtained by coating it with a nanolayer of amorphous carbon, where the added C12H22O11 (sugar) was transformed to Li2CO3 compounds after reacting with residual LiOH on the surface. A thin and uniformly smooth nanolayer (35 nm thick) was observed on the surface of the LiNi0.8Co0.1Mn0.1O2, as confirmed by transmission electron microscopy (TEM). The amount of residual lithium hydroxide (LiOH) was significantly reduced through the formation of lithium carbonate (Li2CO3). As a result, carbon-coated LiNi0.8Co0.1Mn0.1O2 exhibited noticeable improvement in capacity and rate capability and much lower exothermic heat in the charged state at 4.3V. The improved electrochemical performance and thermal stability are attributed to the carbon coating, which reduced the residual lithium hydroxide, protected the cathode material from reacting with the electrolyte, and slowing the incrassation of the solid electrolyte interphase (SEI) film on the surfaces of the oxide particles.C12H22O11 + 12O2 → 12CO2 + 11H2OPACS number: 73.20.At


2019 ◽  
Vol 55 (75) ◽  
pp. 11175-11178 ◽  
Author(s):  
Meichen Zhang ◽  
Yongmao Zhou ◽  
Xiaobo Ding ◽  
Guochun Yan ◽  
Zhixing Wang ◽  
...  

Novel triclinic LiV(PO4)0.9F1.3, characterized through its crystal lattice expansion, ultrafine primary particle size and uniform carbon coating, was fabricated and exhibited excellent electrochemical performance.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Shouxiang Ding ◽  
Mingzheng Zhang ◽  
Runzhi Qin ◽  
Jianjun Fang ◽  
Hengyu Ren ◽  
...  

AbstractRecent years have witnessed a booming interest in grid-scale electrochemical energy storage, where much attention has been paid to the aqueous zinc ion batteries (AZIBs). Among various cathode materials for AZIBs, manganese oxides have risen to prominence due to their high energy density and low cost. However, sluggish reaction kinetics and poor cycling stability dictate against their practical application. Herein, we demonstrate the combined use of defect engineering and interfacial optimization that can simultaneously promote rate capability and cycling stability of MnO2 cathodes. β-MnO2 with abundant oxygen vacancies (VO) and graphene oxide (GO) wrapping is synthesized, in which VO in the bulk accelerate the charge/discharge kinetics while GO on the surfaces inhibits the Mn dissolution. This electrode shows a sustained reversible capacity of ~ 129.6 mAh g−1 even after 2000 cycles at a current rate of 4C, outperforming the state-of-the-art MnO2-based cathodes. The superior performance can be rationalized by the direct interaction between surface VO and the GO coating layer, as well as the regulation of structural evolution of β-MnO2 during cycling. The combinatorial design scheme in this work offers a practical pathway for obtaining high-rate and long-life cathodes for AZIBs.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1946 ◽  
Author(s):  
Hae-Jun Kwon ◽  
Sang-Wook Woo ◽  
Yong-Ju Lee ◽  
Je-Young Kim ◽  
Sung-Man Lee

The electrochemical performance of modified natural graphite (MNG) and artificial graphite (AG) was investigated as a function of electrode density ranging from 1.55 to 1.7 g∙cm−3. The best performance was obtained at 1.55 g∙cm−3 and 1.60 g∙cm−3 for the AG and MNG electrodes, respectively. Both AG, at a density of 1.55 g∙cm−3, and MNG, at a density of 1.60 g∙cm−3, showed quite similar performance with regard to cycling stability and coulombic efficiency during cycling at 30 and 45 °C, while the MNG electrodes at a density of 1.60 g∙cm−3 and 1.7 g∙cm−3 showed better rate performance than the AG electrodes at a density of 1.55 g∙cm−3. The superior rate capability of MNG electrodes can be explained by the following effects: first, their spherical morphology and higher electrode density led to enhanced electrical conductivity. Second, for the MNG sample, favorable electrode tortuosity was retained and thus Li+ transport in the electrode pore was not significantly affected, even at high electrode densities of 1.60 g∙cm−3 and 1.7 g∙cm−3. MNG electrodes also exhibited a similar electrochemical swelling behavior to the AG electrodes.


Author(s):  
V N Koinkar ◽  
B Bhushan

For long durability of magnetic media and head sliders, protective overcoats of hydrogenated amorphous carbon (a-C:H) are generally used. In this study, microtribological studies of hydrogenated amorphous carbon coatings deposited on a single-crystal silicon using three different deposition techniques—sputtering, ion beam and cathodic arc—were studied using atomic force/friction force microscopy (AFM/FFM). Roughnesses of all coatings at two scan sizes of 1 μm × 1 μm and 10 μm × 10 μm are comparable. Surface topography of sputtered carbon coating shows some particulates on the surface. Cathodic arc carbon coating exhibits the lowest coefficient of friction value followed by ion beam and sputtered carbon coatings. Microscratch and wear resistance and nanohardness of cathodic arc carbon coating are superior to those of ion beam and sputtered carbon coatings. Cathodic arc deposited carbon coatings are potential candidates for magnetic disks and heads.


2021 ◽  
Author(s):  
Eun Seop Yoon ◽  
Bong Gill Choi ◽  
Hwan-Jin Jeon

Abstract The development of energy storage electrode materials is important for enhancing the electrochemical performance of supercapacitors. Despite extensive research on improving electrochemical performance with polymer-based materials, electrode materials with micro/nanostructures are needed for fast and efficient ion and electron transfer. In this work, highly ordered phosphomolybdate (PMoO)-grafted polyaniline (PMoO-PAI) deposited onto Au hole-cylinder nanopillar arrays is developed for high-performance pseudocapacitors. The three-dimensional nanostructured arrays are easily fabricated by secondary sputtering lithography, which has recently gained attention and features a high resolution of 10 nm, a high aspect ratio greater than 20, excellent uniformity/accuracy/precision, and compatibility with large area substrates. These 10nm scale Au nanostructures with a high aspect ratio of ~30 on Au substrates facilitate efficient ion and electron transfer. The resultant PMoO-PAI electrode exhibits outstanding electrochemical performance, including a high specific capacitance of 114 mF/cm2, a high-rate capability of 88%, and excellent long-term stability.


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