A Lean-Zinc and Zincophilic Anode for Highly Reversible Zinc Metal Batteries

Lean-zinc anode is a promising configuration that can eliminate the trade-off of energy density and cycle lifetime of zinc metal (Zn⁰) batteries. However, there are rare investigations of lean-Zn anode designs and it remains a grand change to sustain high zinc reversibility under lean zinc conditions. Herein, a lean-Zn anode design based on a hierarchical and zincophilic cobalt metal (Co⁰) nanowire-decorated carbon host, which is derived from a ZnCo bimetallic organic framework, is reported. Within the lean-Zn anode, the trace amount of Zn⁰ acts as a zinc reservoir to make up for any irreversible loss of zinc source upon cycling, while the zincophilic Co⁰ nanowires can guide uniform zinc nucleation and growth through a lattice matching mechanism. Consequently, high Zn⁰ reversibility (average Coulomb efficiency of 99.6% for 4250 cycles), low nucleation overpotential (50.8 mV at 1 mA cm⁻²), and uniform and compact zinc electrodeposition are realized. When coupling the lean-Zn anode with a Zn-containing cathode, the full cell delivers high Coulomb efficiency (99.6% for 4250 cycles on average) and a long lifetime of more than 5000 cycles.