On the Electrochemical Behavior of Aluminum Electrodes in Nonaqueous Electrolyte Solutions of Lithium Salts

Abstract

We studied the electrochemical behavior of aluminum electrodes in solutions comprising ethylene carbonate (EC)–dimethyl carbonate (DMC) and lithium salts: lithium hexafluorophospate (LiPF6) , lithium perchlorate (LiClO4) , or lithium bis(oxalato)borate (LiBOB). Under anodic polarization within the potential range of 3.00–4.00 V in these solutions, aluminum electrodes demonstrate a stable behavior due to their passivation by surface films. Aluminum electrodes passivate in EC–DMC/ LiPF6 and EC–DMC/LiBOB solutions both at 30 and 60°C , whereas these electrodes remain active and corrode in EC–DMC/ LiClO4 solutions. LiBOB may decompose at anodic potentials, thus forming passive films comprising normalB2normalO3 and metal-oxalate species on the aluminum electrodes polarized to 4.50–5.30 V. Li2CO3 , LiF and AlPO4 , and LiCl species were also detected on the electrodes anodically polarized in LiBOB-, LiPF6 -, and LiClO4 -containing solutions, respectively. At some conditions, current oscillations can be developed on aluminum electrodes upon their polarization at constant potentials. These oscillations may relate to the successive formation and dissolution of the passivating surface films formed on electrodes. The development of normalF2P(=O)normalO− species due to the polarization of aluminum electrodes in EC–DMC/ LiPF6 solutions was confirmed by solution NMR studies.

Nitrile functionalized silyl ether with dissolved LiTFSI as new electrolyte solvent for lithium-ion batteries

“…Additionally, dissolved Al 3+ species could migrate to the negative electrode and disturb the SEI chemistry due to the formation of aluminum -lithium alloys [31,32]. In conventional LiPF 6 based electrolytes, aluminum dissolution is suppressed due to the formation of an AlF 3 passivating layer [33,34]. We therefore made cyclic voltammetry investigations on anodic aluminum dissolution using Al as working electrode, as shown in Fig.…”

Electrolytes for electrochemical energy storage

“…LiPF6 is well known for its high solubility and conductivity, great anodic stability, and good capability of passivating Al current collectors at positive potentials. 138 However, LiPF6 has a main disadvantage: it is easy to decompose to LiF and PF5 at temperatures higher than 60 o C. The PF5 can then cause a series of irreversible reactions on both the positrode and negatrode, resulting in performance deterioration. 139,140 LiN(SO2CF3)2 (LiTFSI) and LiC(SO2CF3)3 (LiTFSM) show good thermal and chemical stability compared to LiPF6.…”

Mg(PF6)2-Based Electrolyte Systems: Understanding Electrolyte–Electrode Interactions for the Development of Mg-Ion Batteries

“…Due to the relatively labile P-F bonds, PF 6 − -based electrolytes are able to form passivating layers on various electrodes and commonly used aluminium current collectors, thereby inhibiting continuous breakdown of the electrolyte during battery cycling and corrosion of the current collector, helping to prevent device failure. 13 Despite the ubiquity of LiPF 6 in Li-ion systems, Mg(PF 6 ) 2 has not received the same attention and to the best of our knowledge no direct synthesis of Mg(PF 6 ) 2 compounds have been reported. It is generally thought that the PF 6 − anion decomposes on Mg anodes, forming passivating MgF 2 layers.…”