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

Abstract

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.

Design Strategies toward High‐Utilization Zinc Anodes for Practical Zinc‐Metal Batteries

“…A full cell with a low N/P ratio of 1.34 displayed a high reversible capacity of 398.8 mAh g À 1 at 1 C and demonstrated excellent cycling stability. Li et al [57] further advanced the concept by carburizing a ZnCo bimetallic zeolitic imidazolate framework (ZnCo ZIFÀ L) and simultaneously reducing Zn 2 + and Co 3 + /Co 2 + into metallic Zn and Co, creating a low-Zn, layered, and zincofillic anode structure (Figure 7e). Previous studies have indicated that the reversibility of a metal anode highly depends on the lattice matching between the anode and its nucleation/growth matrix.…”

“…(Reproduced with permission. [57] Copyright 2023, Wiley-VCH.) lattice match with Zn metal, avoiding local charge accumulation issues resulting from an incoherent interface.…”

“…(e) Schematic diagram of protective effect of ZCDC-derived carbon layer modified by zincophilic Co 0 nanowire network on the anode. (Reproduced with permission [57]. Copyright 2023, Wiley-VCH.…”

Backside Coating for Stable Zn Anode with High Utilization Rate

“…To improve the cycling performance of Zn anodes, coating an artificial protective layer on the zinc anodes is commonly used, which effectively homogenizes the zinc plating/stripping process. [9,[16][17][18][19][20][21][22][23][24][25] For example, Zhou et al synthesized nitrogendoped graphene on the surface of zinc foil and achieved good cycling performance at a DOD of 36% for 178 cycles. [26] In another work, Zhao et al created a zincophilic metal-organic framework (MOF) modified layer on Zn foil, which resulted in prolonged cycling at a DOD of 54% for over 700 h. [27] Nevertheless, due to severe volume change and irreversible zinc loss, the inevitable structural damage can easily result in the breakdown of the artificial protective layer, thus stable performance can only be achieved at low current density with low Zn utilization.…”

“…To improve the cycling performance of Zn anodes, coating an artificial protective layer on the zinc anodes is commonly used, which effectively homogenizes the zinc plating/stripping process. [ 9,16–25 ] For example, Zhou et al. synthesized nitrogen‐doped graphene on the surface of zinc foil and achieved good cycling performance at a DOD of 36% for 178 cycles.…”