Preparation of Free-standing and Flexible Li4Ti5O12 electrodes for Li-ion Batteries through an Aqueous Process

The emergence of new flexible and wearable technologies should be performed with environmental and safety considerations1. To meet these challenging aspects, this research focused on a new aqueous slurry formulation for the preparation of flexible and free-standing electrodes for Li-ion batteries. Carbon black, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) were added to the active material. The anode material Li4Ti5O12 was chosen to develop this aqueous system thanks to it compatibility with aqueous process. The PVA/PEG ratio was optimized to obtain flexible and self-sustained electrodes after drying of the suspensions. The DSC (differential scanning calorimetry) measurements demonstrate the interaction between PVA and PEG polymers chains. SEM show good dispersion of all components within the electrodes. The PEG 6000 based electrodes displayed excellent electrochemical performances: up to 90% of the theoretical capacity at high current density (1C rate), which is comparable to the performances reported in the literature for flexible LTO electrode containing either CNTs or metallic current collector. Mild mechanical stress applied to the electrodes allowed to enhance the electrochemical performances. This could be related to the creation of tiny cracks leading to better penetration of the electrolyte in the electrode[2].

References
1- A.Vlad et al., Adv. Energy Mater. 2015, 5, 1402115
2- C. Piffet et al., Chem. Eng. J., 2020, 397, 125508