Biomolecule-guided cation regulation for dendrite-free metal anodes.

Lithium (Li) or zinc (Zn) metal anodes have attracted interest for battery research due to their high theoretical capacities and low redox potentials. However, uncontrollable dendrite growth, especially under high current (>4 mA cm-2), precludes reversable cycling in Li or Zn metal batteries with a high-loading (>4 mAh cm-2), precludes reversable cycling in Li or Zn metal batteries with high-loading (>4 mAh cm-2) cathode. We report a cation regulation mechanism to address this failure. Collagen hydrolysate coated on absorbed glass mat (CH@AGM) can simultaneously induce a deionization shock inside the separator and spread cations on the anode to promote uniform electrodeposition. Employing 24 mAh cm-2 cathodes, Li and Zn metal batteries with CH@AGM delivered 600 cycles with a Coulombic efficiency of 99.7%. In comparison, pristine Li and Zn metal batteries only survive for 10 and 100 cycles, respectively. This approach enabled 400 cycles in a 200 Ah-class Zn metal battery, which suggests a scalable method to achieve dendrite-free anodes in various batteries.