Thermoplastic Polyurethane Derived from CO for the Cathode Binder in Li-CO Battery.

High-energy-density Li-CO batteries are promising candidates for large-capacity energy storage systems. However, the development of Li-CO batteries has been hindered by low cycle life and high overpotential. In this study, we propose a CO-based thermoplastic polyurethane (CO-based TPU) with CO adsorption properties and excellent self-healing performance to replace traditional polyvinylidene fluoride (PVDF) as the cathode binder. The CO-based TPU enhances the interfacial concentration of CO at the cathode/electrolyte interfaces, effectively increasing the discharge voltage and lowering the charge voltage of Li-CO batteries. Moreover, the CO fixed by urethane groups (-NH-COO-) in the CO-based TPU are difficult to shuttle to and corrode the Li anode, minimizing CO side reactions with lithium metal and improving the cycling performance of Li-CO batteries. In this work, Li-CO batteries with CO-based TPU as the multifunctional binders exhibit stable cycling performance for 52 cycles at a current density of 0.2 A g, with a distinctly lower polarization voltage than PVDF bound Li-CO batteries.