Effect of Impurities on Electrochemical Performance of Low-Purity Natural Graphite As Anode Active Material for Lithium Ion Batteries

2021 ◽  
Vol 1036 ◽  
pp. 35-44
Author(s):  
Ling Fang Ruan ◽  
Jia Wei Wang ◽  
Shao Ming Ying

Silicon-based anode materials have been widely discussed by researchers because of its high theoretical capacity, abundant resources and low working voltage platform,which has been considered to be the most promising anode materials for lithium-ion batteries. However,there are some problems existing in the silicon-based anode materials greatly limit its wide application: during the process of charge/discharge, the materials are prone to about 300% volume expansion, which will resultin huge stress-strain and crushing or collapse on the anods; in the process of lithium removal, there is some reaction between active material and current collector, which creat an increase in the thickness of the solid phase electrolytic layer(SEI film); during charging and discharging, with the increase of cycle times, cracks will appear on the surface of silicon-based anode materials, which will cause the batteries life to decline. In order to solve these problems, firstly, we summarize the design of porous structure of nanometer sized silicon-based materials and focus on the construction of three-dimensional structural silicon-based materials, which using natural biomass, nanoporous carbon and metal organic framework as structural template. The three-dimensional structure not only increases the channel of lithium-ion intercalation and the rate of ion intercalation, but also makes the structure more stable than one-dimensional or two-dimensional. Secondly, the Si/C composite, SiOx composite and alloying treatment can improve the volume expansion effection, increase the rate of lithium-ion deblocking and optimize the electrochemical performance of the material. The composite materials are usually coated with elastic conductive materials on the surface to reduce the stress, increase the conductivity and improve the electrochemical performance. Finally, the future research direction of silicon-based anode materials is prospected.


Author(s):  
Yanping Dang ◽  
Wangyu Liu ◽  
Weigui Xie ◽  
Weiping Qiu

Abstract The anode and cathode pieces are vital components of lithium-ion batteries. The coating surface density of active material is a significant parameter involved during the fabrication of electrodes and has considerable impact on battery performance. In this paper, anode and cathode pieces are prepared with different surface densities within the allowable range. The anode and cathode pieces are first graded respectively and then matched up according to different surface density ranges. Afterward, the electrodes are assembled with commercial polypropylene separator in 18,650 cell case and infused with electrolyte. The cathode is constituted with a mixture of nickel cobalt manganese (NCM) ternary material and lithium manganese oxide coated on aluminum foil, while the anode is composed of graphite coated on copper foil. The electrochemical performance and safety properties were tested to investigate the influence of the coating surface density of electrodes and optimize the electrochemical performance by regulating the matching surface density of electrodes. The results indicate that larger surface density of both cathode and anode can provide better battery consistency, while smaller surface density can contribute to better specific capacity and smaller capacity loss after cycling. Modest cost and superior properties can be achieved for lithium-ion batteries by reasonably matching the surface density of anodes and cathodes pieces.


2001 ◽  
Vol 46 (8) ◽  
pp. 1161-1168 ◽  
Author(s):  
M. Mohamedi ◽  
Seo-Jae Lee ◽  
D. Takahashi ◽  
M. Nishizawa ◽  
T. Itoh ◽  
...  

2019 ◽  
Vol 3 (8) ◽  
pp. 1929-1936
Author(s):  
Go Tei ◽  
Ryohei Miyamae ◽  
Akira Kano

Graphite-like Ca0.6B1.2C4.8 is reported as a novel anode active material for lithium-ion batteries.


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