Achieving High-Performance Spherical Natural Graphite Anode through a Modified Carbon Coating for Lithium-Ion Batteries

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.

Modeling the Effect of the Loss of Cyclable Lithium on the Performance Degradation of a Lithium-Ion Battery

This paper reports a modeling methodology to predict the effect of the loss of cyclable lithium of a lithium-ion battery (LIB) cell comprised of a LiNi0.6Co0.2Mn0.2O2 cathode, natural graphite anode, and an organic electrolyte on the discharge behavior. A one-dimensional model based on a finite element method is presented to calculate the discharge behaviors of an LIB cell during galvanostatic discharge for various levels of the loss of cyclable lithium. Modeling results for the variation of the cell voltage of the LIB cell are compared with experimental measurements during galvanostatic discharge at various discharge rates for three different levels of the loss of cyclable lithium to validate the model. The calculation results obtained from the model are in good agreement with the experimental measurements. On the basis of the validated modeling approach, the effects of the loss of cyclable lithium on the discharge capacity and available discharge power of the LIB cell are estimated. The modeling results exhibit strong dependencies of the discharge behavior of an LIB cell on the discharge C-rate and the loss of cyclable lithium.

Environment Impact Analysis of Natural Graphite Anode Material Production

A quantitative analysis on the environment impact of natural graphite anode material is carried out based on life cycle assessment (LCA) method in this paper. The results show that, the main environment impact categories are human toxicity potential, particulate matter formation potential and marine ecotoxicity potential, which account for 26%, 19% and 15% of total environment impacts, respectively. The processes of production, purification and surface modification cause the strongest impact on the environment, because they consume a large number of electricity. Under the current electricity structure of China, improving the production technology and reducing the energy consumptions of purification and surface modification, are the effective methods of environment impact reduction for LIB anode materials.

Energy Consumption and Carbon Emission Analysis of Natural Graphite Anode Material for Lithium Batteries

The production process of nature graphite anode material is divided into four stages, namely mining, beneficiation, purification and processing. Carbon emission and energy consumption during the whole process were quantified and analyzed in this study. The energy consumption and pollutant emissions in the production process were calculated in accordance with the method of life cycle assessment, and the carbon emission analysis was conducted by IPCC method. The life cycle energy consumption of 1 ton natural graphite anode material is 112.48GJ, and the processing stage contributes 41.71%. The results show that coke oven gas and raw coal are the main energy consumption in the whole life cycle of natural graphite anode material, which account for 32.33% and 23.41% of the total energy consumption, respectively. Furthermore, the carbon emission of 1 ton of natural graphite anode material is 5315.91kgCO2-eq, and mainly comes from raw coal and electricity which contribute 23.98% and 20.99% to the total carbon emission respectively, and CO2 is the largest carbon emission contributed 98.69% to total carbon emission. Finally, the carbon emissions are sensitive to the coke oven gas, raw coal, diesel and electricity, and insensitive to fuel oil.

Enhanced electrochemical properties of a natural graphite anode using a promising crosslinked ionomer binder in Li-ion batteries

A crosslinked ionomer binder was prepared and used in graphite anodes for Li-ion batteries. These binder-based anodes exhibit enhanced electrochemical performance due to the formation of hydrogen bonds and the release of conductive Li+.