scholarly journals Polyethylene Oxide as a Multifunctional Binder for High-Performance Ternary Layered Cathodes

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3992
Author(s):  
Jinshan Mo ◽  
Dongmei Zhang ◽  
Mingzhe Sun ◽  
Lehao Liu ◽  
Weihao Hu ◽  
...  

Nickel cobalt manganese ternary cathode materials are some of the most promising cathode materials in lithium-ion batteries, due to their high specific capacity, low cost, etc. However, they do have a few disadvantages, such as an unstable cycle performance and a poor rate performance. In this work, polyethylene oxide (PEO) with high ionic conductance and flexibility was utilized as a multifunctional binder to improve the electrochemical performance of LiNi0.6Co0.2Mn0.2O2 cathode materials. Scanning electron microscopy showed that the addition of PEO can greatly improve the adhesion of the electrode components and simultaneously enhance the integrity of the electrode. Thus, the PEO-based electrode (20 wt% PEO in PEO/PVDF) shows a high electronic conductivity of 19.8 S/cm, which is around 15,000 times that of the pristine PVDF-based electrode. Moreover, the PEO-based electrode exhibits better cycling stability and rate performance, i.e., the capacity increases from 131.1 mAh/g to 147.3 mAh/g at 2 C with 20 wt% PEO addition. Electrochemical impedance measurements further indicate that the addition of the PEO binder can reduce the electrode resistance and protect the LiNi0.6Co0.2Mn0.2O2 cathode materials from the liquid electrolyte attack. This work offers a simple yet effective method to improve the cycling performance of the ternary cathode materials by adding an appropriate amount of PEO as a binder in the electrode fabrication process.

2021 ◽  
Vol 8 ◽  
Author(s):  
Xianguang Zeng ◽  
Jing Peng ◽  
Huafeng Zhu ◽  
Yong Gong ◽  
Xi Huang

Li2ZnTi2.9Cr0.1O8 and Li2ZnTi3O8 were synthesized by the liquid phase method and then studied comparatively using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), galvanostatic charge–discharge testing, cyclic stability testing, rate performance testing, and electrochemical impedance spectroscopy (EIS). The results showed that Cr-doped Li2ZnTi3O8 exhibited much improved cycle performance and rate performance compared with Li2ZnTi3O8. Li2ZnTi2.9Cr0.1O8 exhibited a discharge ability of 156.7 and 107.5 mA h g−1 at current densities of 2 and 5 A g−1, respectively. In addition, even at a current density of 1 A g−1, a reversible capacity of 162.2 mA h g−1 was maintained after 200 cycles. The improved electrochemical properties of Li2ZnTi2.9Cr0.1O8 are due to its increased electrical conductivity.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7641
Author(s):  
Kaibin Fang ◽  
Jihua Zhu ◽  
Qian Xie ◽  
Yifei Men ◽  
Wei Yang ◽  
...  

A series of carbon-coated LiMn1−xFexPO4 (x = 0, 0.1, 0.2, 0.3, 0.4) materials are successfully constructed using glucose as carbon sources via sol-gel processes. The morphology of the synthesized material particles are more regular and particle sizes are more homogeneous. The carbon-coated LiMn0.8Fe0.2PO4 material obtains the discharge specific capacity of 152.5 mAh·g−1 at 0.1 C rate and its discharge specific capacity reaches 95.7 mAh·g−1 at 5 C rate. Iron doping offers a viable way to improve the electronic conductivity and lattice defects of materials, as well as improving transmission kinetics, thereby improving the rate performance and cycle performance of materials, which is an effective method to promote the electrical properties.


2012 ◽  
Vol 1440 ◽  
Author(s):  
Jiajia Tan ◽  
Ashutosh Tiwari

ABSTRACTLi2FeP2O7 is a newly developed polyanionic cathode material for high performance lithium ion batteries. It is considered very attractive due to its large specific capacity, good thermal and chemical stability, and environmental benignity. However, the application of Li2FeP2O7 is limited by its low ionic and electronic conductivities. To overcome the above problem, a solution-based technique was successfully developed to synthesize Li2FeP2O7 powders with very fine and uniform particle size (< 1 μm), achieving much faster kinetics. The obtained Li2FeP2O7 powders were tested in lithium ion batteries by measurements of cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge cycling. We found that the modified Li2FeP2O7 cathode could maintain a relatively high capacity even at fast discharge rates.


2019 ◽  
Author(s):  
Panpan Wang ◽  
Yue Du ◽  
Baoyou Zhang ◽  
Yanxin Yao ◽  
Yuchen Xiao ◽  
...  

The <i>β-</i>phase lithium vanadium oxide bronze (<i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub>) with high theoretic specific capacity up to 440 mAh g<sup>-1</sup> is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of <i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> cathode using both reduced oxide graphene and ionic conductor LaPO<sub>4</sub>, which significantly promotes the electronic transfer and Li<sup>+</sup> diffusion rate, respectively. As a result, the rGO/LaPO<sub>4</sub>/Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g<sup>-1</sup> with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g<sup>-1</sup>, and acceptable specific capacity of 170.3 mAh g<sup>-1</sup> at high current density of 400 mA g<sup>-1</sup>. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, <i>ex-situ </i>X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our results provide an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.


2018 ◽  
Vol 913 ◽  
pp. 779-785
Author(s):  
Zhong Yi Chen ◽  
Kun Ma ◽  
De Guo Zhou ◽  
Yan Liu ◽  
Yan Zong Zhang

A novel membrane electrode was fabricated by coating conductive slurry (K/Graphene composites as its important component) on copper foil. The membrane electrode, as anode of lithium ion battery, exhibited excellent columbic efficiency and specific capacity of 831 mAh g-1 after 1000 cycles. The K/Graphene composites presented a multi-layer nanostructure. It provided not only more intercalation space and intercalation sites for Li+ during the Li+ intercalation/extraction, but also alleviated the agglomeration of dispersed nanocrystals, as well as decreased the electrochemical impedance. The results suggest that the membrane electrode holds great potential as an anode material for LIBs.


2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Byeong Gwan Lee ◽  
Yong Joon Park

AbstractLithia-based materials are promising cathodes based on an anionic (oxygen) redox reaction for lithium ion batteries due to their high capacity and stable cyclic performance. In this study, the properties of a lithia-based cathode activated by Li2RuO3 were characterized. Ru-based oxides are expected to act as good catalysts because they can play a role in stabilizing the anion redox reaction. Their high electronic conductivity is also attractive because it can compensate for the low conductivity of lithia. The lithia/Li2RuO3 nanocomposites show stable cyclic performance until a capacity limit of 500 mAh g−1 is reached, which is below the theoretical capacity (897 mAh g−1) but superior to other lithia-based cathodes. In the XPS analysis, while the Ru 3d peaks in the spectra barely changed, peroxo-like (O2)n− species reversibly formed and dissociated during cycling. This clearly confirms that the capacity of the lithia/Li2RuO3 nanocomposites can mostly be attributed to the anionic (oxygen) redox reaction.


2019 ◽  
Vol 13 (02) ◽  
pp. 2050005
Author(s):  
Guisheng Liang ◽  
Xingxing Jin ◽  
Cihui Huang ◽  
Lijie Luo ◽  
Yongjun Chen ◽  
...  

Li3VO4 has gained significant attention as a promising anode material for lithium-ion batteries owing to its high specific capacity, low cost and safe working potential. Unfortunately, its disappointing electronic conductivity limits its rate performance. To address this problem, a series of Cr[Formula: see text]-doped Li3VO4 compounds are synthesized by solid-state reaction. The obtained Li[Formula: see text]Cr[Formula: see text]V[Formula: see text]O4 compounds ([Formula: see text] and 0.02) have the same orthorhombic crystal structure (Pnm21 space group), suggesting the successful Cr[Formula: see text] doping in Li3VO4. Compared with Li3VO4, Li[Formula: see text]Cr[Formula: see text]V[Formula: see text]O4 exhibits a two orders of magnitude larger electronic conductivity. Additional benefits of the Cr[Formula: see text] doping include the increase of the Li[Formula: see text] diffusion coefficient and the decrease of the particle size. Consequently, Li[Formula: see text]Cr[Formula: see text]V[Formula: see text]O4 displays not only a large reversible capacity (363[Formula: see text]mAh g[Formula: see text] at 60[Formula: see text]mA g[Formula: see text] and superior cyclic stability (86.6% capacity retention after 1000 cycles at 1200[Formula: see text]mA g[Formula: see text] but also decent rate performance (147[Formula: see text]mAh g[Formula: see text] at 1200[Formula: see text]mA g[Formula: see text].


NANO ◽  
2021 ◽  
pp. 2150119
Author(s):  
M. M. Xia ◽  
J. Li ◽  
Y. Y. Zhang ◽  
D. N. Kang ◽  
Y. L. Zhang

Nanosized TiO2 has been actively developed as a low-cost and environment-friendly anode material for lithium-ion batteries (LIBs), but its poor electronic conductivity seriously restricts its practical applications. This drawback is addressed in this work by the fabrication of one-dimensional mesoporous graphene@Ag@TiO2 composite nanofibers as anode materials for high-performance LIBs. The materials were prepared via electrospinning combined with annealing treatment, and the effects of graphene addition on the microstructure and electrochemical performance of the resulting mesoporous graphene@Ag@TiO2 nanofibers were investigated in detail. Ag@TiO2 nanofibers with the optimal amount of graphene displayed a maximum initial discharge capacity of [Formula: see text] at [Formula: see text] and retained a discharge capacity of [Formula: see text] at [Formula: see text] after 100 cycles. These results reflect the excellent cycling stability of the material. The average specific discharge capacity of the nanofibers ([Formula: see text] at [Formula: see text] was two-fold higher than that of samples without graphene, and their discharge capacity returned to [Formula: see text] (approximately [Formula: see text] for other nanofibers) when the current density was recovered to the initial value ([Formula: see text]. Electrochemical impedance spectroscopic measurements confirmed that the conductivity of the electrode was [Formula: see text], which is higher than that of bare mesoporous Ag@TiO2 ([Formula: see text]). Thus, one-dimensional mesoporous graphene@Ag@TiO2 nanofibers can be regarded as a promising anode material for LIBs.


2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Renáta Oriňáková ◽  
Andrea Fedorková ◽  
Andrej Oriňák

AbstractRechargeable lithium-ion batteries (LIBs) have been the most commonly used batteries in the portable electronics market for many years. Polypyrrole (PPy) was now investigated as a conducting addition agent to enhance the cathode and anode materials performance in LIBs. Actual development in the synthesis and modification of the most promising cathode materials, LiFePO4, is described in this mini-review. The main aim of this mini-review is to highlight the effect of PPy based conducting polymer films on the electrochemical efficiency of LiFePO4 based cathode materials for LIBs summarizing our own research. Influence of the polyethylene glycol (PEG) additive in the PPy coating layer was evaluated. The improved electrochemical performance can be attributed to the enhanced electronic conductivity, higher solubility of ions originating from the electrolyte, higher movability of dissolved Li+ ions, and improved structural flexibility resulting from the incorporation of the PPy or PPy/PEG conducting polymer layer. The stabilizing effect of PEG in PPy was reflected in lowered cross-linking and reduced structural defects and, in consequence, in higher specific capacity of PPy/PEG-LiFePO4 cathodes compared to that of PPy-LiFePO4 cathodes and bare LiFePO4 cathodes.


2019 ◽  
Vol 7 (23) ◽  
pp. 14253-14259 ◽  
Author(s):  
Huanhuan Xie ◽  
Yu Qie ◽  
Muhammad Imran ◽  
Qiang Sun

Motivated by the advantages of inherent high electronic conductivity and ordered porosity of topological semimetal monoclinic C16 (m-C16), we explore its possible use as a lithium-ion battery anode material.


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