电解质
材料科学
热重分析
热稳定性
阴极
差示扫描量热法
相(物质)
化学工程
分析化学(期刊)
热分析
量热法
热的
热力学
物理化学
有机化学
化学
电极
物理
工程类
作者
Yiqing Huang,Yuh‐Chieh Lin,David M. Jenkins,Natasha A. Chernova,Youngmin Chung,Balachandran Radhakrishnan,Iek‐Heng Chu,J. H. Fang,Qi Wang,Fredrick Omenya,Shyue Ping Ong,M. Stanley Whittingham
标识
DOI:10.1021/acsami.5b12081
摘要
The thermal stability of electrochemically delithiated Li0.1Ni0.8Co0.15Al0.05O2 (NCA), FePO4 (FP), Mn0.8Fe0.2PO4 (MFP), hydrothermally synthesized VOPO4, LiVOPO4, and electrochemically lithiated Li2VOPO4 is investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis, coupled with mass spectrometry (TGA-MS). The thermal stability of the delithiated materials is found to be in the order of NCA < VOPO4 < MFP < FP. Unlike the layered oxides and MFP, VOPO4 does not evolve O2 on heating. Thus, VOPO4 is less likely to cause a thermal run-away phenomenon in batteries at elevated temperature and so is inherently safer. The lithiated materials LiVOPO4, Li2VOPO4, and LiNi0.8Co0.15Al0.05O2 are found to be stable in the presence of electrolyte, but sealed-capsule high-pressure experiments show a phase transformation of VOPO4 → HVOPO4 → H2VOPO4 when VOPO4 reacts with electrolyte (1 M LiPF6 in EC/DMC = 1:1) between 200 and 300 °C. Using first-principles calculations, we confirm that the charged VOPO4 cathode is indeed predicted to be marginally less stable than FP but significantly more stable than NCA in the absence of electrolyte. An analysis of the reaction equilibria between VOPO4 and EC using a multicomponent phase diagram approach yields products and reaction enthalpies that are highly consistent with the experiment results.
科研通智能强力驱动
Strongly Powered by AbleSci AI