电解质
阴极
电化学
锂(药物)
材料科学
热分解
电极
分解
无机化学
碳纤维
化学工程
热液循环
化学
复合数
复合材料
有机化学
物理化学
内分泌学
工程类
医学
作者
Yi-Hung Liu,Wei-Cheng Chen,Chung-Hsuan Hsueh,Cheng-Liang Hsu
标识
DOI:10.1016/j.mtchem.2022.100934
摘要
We report on the improved electrochemical performance of a high-voltage LiNi 0 . 5 Mn 1 . 5 O 4 (LNMO) cathode using surface-modified carbon blacks (CBs) as conductive agents. Facile modifications of CBs were achieved using thermal, urea-based hydrothermal, and acid oxidation treatments. The material properties of the modified CBs, LNMO-based electrode surface, and electrolyte compositions were investigated and correlated. Based on the distribution of the decomposition deposits on the surface of the electrode, it is confirmed that CB, rather than the LNMO active material, dominates the electrolyte decomposition site at a high voltage, owing to its relatively high surface area for the reaction. Additionally, compared with the pristine CB, the hydrothermally treated N-doped CB (HCB) improves the electrochemical performance of the LNMO cathode, although the thermally treated sample exhibits the most adverse influence, followed by the oxidized one. The LNMO/HCB cathode attains optimum capacity retention (approximately 95%) for 100 cycles (1 C) and a high rate capability (70%, 5 C/0.2 C), corresponding to a lowered resistance at the cathode–electrolyte interface. Furthermore, HCB with a limited specific surface area and increased defects, as well as additional pyrrolic-N and pyridinic-N groups, substantially reduces the decomposition deposits on the surface of the electrode and the decomposition products in the electrolyte. These phenomena account for the improved electrochemical performance of the LNMO/HCB cathode. • N-doped CB is successfully obtained via urea-based hydrothermal reaction. • LNMO cathode containing N-doped CB exhibits favorable cycling and rate performances. • CB, rather than LNMO, dominates the electrolyte decomposition site at a high voltage. • Stable CEI can be formed on LNMO cathode containing N-doped CB. • CB with more pyrrolic- and pyridinic-N groups can mitigate electrolyte decomposition.
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