Abstract
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.
Highlights
Graphitic carbons, such as natural graphite (NG) and artificial graphite (AG), are currently used as negative electrode material for Li-ion batteries (LiBs)
Considering the fact that commercial carboncoated NG (CNG) suffers from significant swelling due to the additional formation and growth of an solid electrolyte interface (SEI) film during prolonged cycling [4], it appears that the electrolyte decomposition required to form the SEI film during cycling was effectively suppressed in the modified natural graphite (MNG) and AG electrodes
MNG powders are successfully synthesized by using a mixture of coal pitch and petroleum pitch as a carbon precursor for a modified carbon coating
Summary
Graphitic carbons, such as natural graphite (NG) and artificial graphite (AG), are currently used as negative electrode material for Li-ion batteries (LiBs). It is known that LiBs using NG negative electrodes exhibit significant capacity fade during extended cycling, and only a moderate rate capability, which limits their application to devices requiring long-term cycling capability and high power densities, such as electric vehicles (EV) and energy storage systems (ESS) [2,3,4,5]. NG samples obtained through the modified carbon coating process is abbreviated to “MNG” It appears that the cycle performance of the MNG anode is superior to that of the CNG anode. In light of the current practical situation in which AG is preferred over CNG in sectors requiring high power densities and extended cycling performance, it is meaningful to make a direct comparison between AG and MNG as anode materials. We compared the electrochemical properties of AG and MNG, including discharge capacity, initial and subsequent cycle efficiency, cyclability, and charge/discharge rate performance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
