Application of a Commercially-Available Fluorine-Free Thermoplastic Elastomer as a Binder for High-Power Li-Ion Battery Electrodes

Lotader 5500, a commercially-available polyethylene-co-ethyl acrylate-co-maleic anhydride thermoplastic elastomer, is investigated as a new binder for Li-ion battery composite electrodes with LiFePO4 and Li4Ti5O12. This binder was chosen to enhance the cohesion and adhesion properties of the composite electrode it binds through its reactive functional groups; moreover, the absence of fluorine in its composition renders it more suitable than polyvinylidene fluoride (PVDF) in the battery recycling process, which often relies on pyrolysis. Lotader 5500's insolubility in a carbonate electrolyte is demonstrated, as well as its similar electrochemical behavior to PVDF in the 50 mV to 4.2 V range vs. Li+/Li. After demonstrating the high-rate performance of the half-cells, full cells were assembled, and cycled 1,000 times (charged at a constant voltage of 2.4 V and discharged at 10D), and all exhibit a final capacity of approximately 70 mAh.g−1.