Missing-Linker Defect\nFunctionalized Metal–Organic\nFrameworks Accelerating Zinc Ion Conduction for Ultrastable All-Solid-State\nZinc Metal Batteries

Solid-state polymer electrolytes (SPEs) are promising\nfor high-performance\nzinc metal batteries (ZMBs), but they encounter critical challenges\nof low ionic conductivity, limited Zn<sup>2+</sup> transference number\n(<i>t</i><sub>Zn2+</sub>), and an unstable electrolyte-electrode\ninterface. Here, we present an effective approach involving a missing-linker\nmetallic organic framework (MOF)-catalyzed poly(ethylene glycol) diacrylate\n(PEGDA)/polyacrylamide (PAM) copolymer SPE for single Zn<sup>2+</sup> conduction and seamless electrolyte-electrode contact. The single-Zn<sup>2+</sup> conduction is facilitated by the anchoring of the OTF<sup>–</sup> anions onto the unsaturated metal sites of missing-linker\nMOF, while the PEGDA and PAM chains in competitive coordination with\nZn<sup>2+</sup> ions promote rapid Zn ion transport. Our all-solid-state\nelectrolyte simultaneously achieves a superior ionic conductivity\nof 1.52 mS cm<sup>–1</sup> and a high <i>t</i><sub>Zn2+</sub> of 0.83 at room temperature, alongside uniform Zn metal\ndeposition (1000 cycles in symmetric cells) and high Zn plating/striping\nefficiencies (>99% after 600 cycles in asymmetric cells). Applications\nof our SPE in Zn//VO<sub>2</sub> full cells are further demonstrated\nwith a long lifespan of 2000 cycles and an extremely low-capacity\ndegradation rate of 0.012% per cycle. This work provides an effective\nstrategy for using a missing-linker MOF to catalyze competitively\ncoordinating copolymers for accelerating Zn<sup>2+</sup> ion conduction,\nassisting the future design of all-solid-state ZMBs.