A lean‐zinc anode battery based on metal–organic framework‐derived carbon

Abstract

AbstractImproving zinc metal (Zn0) reversibility and minimizing the N/P ratio are critical to boosting the energy density of Zn0 batteries. However, in reality, an excess Zn source is usually adopted to offset the irreversible zinc loss and guarantee sufficient zinc cycling, which sacrifices the energy density and leads to poor practicability of Zn0 batteries. To address the above conundrum, here, we report a lean‐Zn and hierarchical anode based on metal–organic framework (MOF)‐derived carbon, where trace Zn0 is pre‐reserved within the anode structure to make up for any irreversible zinc source loss. This allows us to construct low N/P ratio Zn0 full cells when coupling the lean‐Zn anode with Zn‐containing cathodes. Impressively, high Zn0 reversibility (average Coulombic efficiency of 99.4% for 3000 cycles) and long full‐cell lifetime (92% capacity retention after 900 cycles) were realized even under the harsh lean‐Zn condition (N/P ratio: 1.34). The excellent Zn reversibility is attributed to the hierarchy structure that homogenizes zinc ion flux and electric field distribution, as confirmed by theoretical simulations, which therefore stabilizes Zn0 evolution. The lean‐Zn anode design strategy will provide new insights into construction of high‐energy Zn0 batteries for practical applications.