Liao Xingqun, Hu Dalin, Yu Lijuan, Li Bin, Xiao Feng, Wang Shanxing
School of Chemistry and Materials Engineering, Huizhou University, Huizhou, China.
Huizhou Highpower Technology, Huizhou, China.
PLoS One. 2024 Dec 19;19(12):e0311943. doi: 10.1371/journal.pone.0311943. eCollection 2024.
The issue of long charging time for electric vehicles has been a matter of serious concern, and the problem is mainly stemmed from the graphite anode. The slow kinetics of pure graphite can lead to the formation of the lithium metal during fast charging, which triggers cycle degradation and safety issues of electric vehicles. In order to ameliorate the fast charging issue, a spherical hard carbon/graphite porous electrode is devised. Based on this, the discharge capacity ratio at 3C shows an improvement of about 40% at 25°C and at 1C shows an improvement of about 18% at 0°C. Additionally, the 300-cycle capacity retentions exhibit increases of 12% and 14% at temperature of 25°C and 50°C, respectively. Generally, the analysis shows that the spherical hard carbon/graphite porous electrode has more uniform porous structure, shorter transport path, less nano-scale powder and a certain voltage buffer ability compared to the pure graphite powder system, which enhance the ion transport kinetics, and reduce the side reactions under the high temperature, so as to effectively improve the fast charging performance and cycle life of the LIBs. It is also proved that the kinetics improvement is not only attributed to the high kinetics inherited from the instinct of hard carbon, but also the porous electrode structures constructed by the two-size powder system of graphite and hard carbon.
电动汽车充电时间长的问题一直备受严重关注，而该问题主要源于石墨阳极。纯石墨的缓慢动力学在快速充电过程中会导致锂金属的形成，这引发了电动汽车的循环性能下降和安全问题。为了改善快速充电问题，设计了一种球形硬碳/石墨多孔电极。基于此，在25°C下，3C倍率下的放电容量比提高了约40%，在0°C下，1C倍率下的放电容量比提高了约18%。此外，在25°C和50°C温度下，300次循环的容量保持率分别提高了12%和14%。总体而言，分析表明，与纯石墨粉末体系相比，球形硬碳/石墨多孔电极具有更均匀的多孔结构、更短的传输路径、更少的纳米级粉末以及一定的电压缓冲能力，这增强了离子传输动力学，并减少了高温下的副反应，从而有效提高了锂离子电池的快速充电性能和循环寿命。还证明了动力学的改善不仅归因于硬碳本身所具有的高动力学特性，还归因于由石墨和硬碳两种尺寸粉末体系构建的多孔电极结构。
