Multipolar Conjugated Polymer Framework Derived Ionic Sieves via Electronic Modulation for Long-Life All-Solid-State Li Batteries.

Here, we build a tunable multipolar conjugated polymer framework platform via pore wall chemistry to probe the role of electronic structure engineering in improving the Li+ conduction by theoretical studies. Guided by theoretical prediction, we develop a new cyano-vinylene-linked multipolar polymer framework namely CNF-COF, acting as efficient ion sieves to modify polymer electrolytes for long-lifespan all-solid-state (ASS) Li metal batteries. The cyano and fluorine groups dual-decoration in CNF-COF favorably regulates the electronic structure via multipolar donor-acceptor electronic effects to afford proper energy band structure and abundant electron-rich sites for enhanced anti-oxidative ability, facilitated ion-pair dissociation and suppressed anion movements. Thus, the CNF-COF incorporation into poly (ethylene oxide) (PEO) electrolytes not only renders selective rapid Li+ conduction but also facilitates the Li dendrite suppression. Specifically, the constructed composite electrolyte with an ultralow CNF-COF content of only 0.5 wt% is endowed with a high ionic conductivity of 0.634 mS cm-1 at 60 °C and a large Li+ transference number of 0.81. As such, the Li symmetric cell delivers stable Li plating/stripping over 1400 h. Impressively, t he assembled ASS Li battery under 60 °C allows for stable cycling over 2000 cycles at 1 C and over 1000 cycles even at 2 C.