A rigid-flexible coupling poly(vinylene carbonate) based cross-linked network: A versatile polymer platform for solid-state polymer lithium batteries

Solid-state polymer lithium batteries have great potential in flexible/wearable electronics, however, it still has been struggling with insufficient mechanical properties of polymer electrolytes, which have great possibility to result in safety issues in the abuse condition. Herein, we present a poly(vinylene carbonate)-based cross-linked network as a promising polymer platform via a rigid-flexible coupling polymer design for lithium battery applications, which is versatile for high performance electrolyte and binder. The as-prepared cross-linked network polymer is prepared by the nucleophilic attack of flexible polyoxyethylene bis(amine) and oxidation-resistant aminopropionitrile to rigid poly(vinylene carbonate) framework. This reaction chemistry shows a facile, fast solidification of electrolyte precursor solutions without the employment of any initiators. It is demonstrated that the resultant solid polymer electrolyte with this cross-linked network polymer presents excellent mechanical properties without any supporting materials, with a tensile strength of 22 MPa and an elongation-at-break value of 350%. Furthermore, it exhibits excellent thermal stabilities, decent ionic conductivities, good compatibility with electrodes especially lithium metal anode. Benefited from these merits, excellent cycling performance of 4.3 V-class LiCoO2/Li cell under 60 °C can be achieved, with a capacity retention of 80% after 150 cycles at 0.5 C. More striking, employing this cross-linked network polymer as both the electrolyte host and electrode binder, lithium batteries exhibit superior cycle performance at both ambient and high temperatures. This work indicates that the as-prepared cross-linked network polymer can serve as a polymer platform, which can provide high performance electrolyte and binder that are urgently needed for lithium batteries.