Effects of binder content on manganese dissolution and electrochemical performances of spinel lithium manganese oxide cathodes for lithium ion batteries

• Spinel LMO electrodes are fabricated with 3–10 wt.% PVdF binder content.
• Increased binder content leads to reduced Mn dissolution and superior cyclability at 60 °C.
• Rate capability is not deteriorated by increased PVdF content.
• LMO electrodes with higher binder content exhibit lower electrode impedance.

In this study, the effects of the polyvinylidene fluoride (PVdF) binder on the Mn dissolution behavior and electrochemical performances of LiMn2O4 (LMO) electrodes are investigated. It is found that increasing the PVdF content (3, 5, 7, and 10 wt.%) leads to reduced Mn dissolution, and thus superior cycle performance at elevated temperature (60 °C). This can be ascribed to increased binder coverage on the LMO surface, as evidenced by X-ray photoelectron spectroscopy measurements, which acts a role as a passivation layer for Mn dissolution. The rate capability of the LMO electrode is hardly deteriorated as the PVdF content increases, despite the increasing surface coverage. Electrochemical impedance measurements reveal that the LMO electrode with higher binder loading exhibits lower electrode impedance, which is suggested to be due to enhanced electronic passage through the composite LMO electrode.