Hydrogen‐Substituted Graphdiyne Ion Tunnels Directing Concentration Redistribution for Commercial‐Grade Dendrite‐Free Zinc Anodes

Abstract

Current aqueous Zn batteries (ZBs) seriously suffer from dendrite issues caused by rough electrode surfaces. Despite significant efforts in prolonging lifespan of these batteries, little effort has been devoted to dendrite elimination in commercial‐grade cathode loading mass. Instead, demonstrations have only been done at the laboratory level (≤2 mg cm−2). Additionally, new dilemmas regarding change of the proton‐storage behavior and interface pulverization have emerged in turn. Herein, hydrogen‐substituted graphdiyne (HsGDY), with sub‐ångström level ion tunnels and robust chemical stability, is designed as an artificial interface layer to address these issues. This strategy prolongs the symmetric cell lifespan to >2400 h (100 days), which is 37 times larger than without protection (63 h). The simulation of dual fields reveals that HsGDY can redistribute the Zn2+ concentration field by spatially forcing Zn2+ to deviate from the irregular electric field. During practical use, the as‐assembled full batteries deliver a long lifespan 50 000 cycles and remain stable even at a commercial‐grade cathode loading mass of up to 22.95 mg cm−2. This HsGDY‐protection methodology represents great progress in Zn dendrite protection and demonstrates enormous potential in metal batteries.

Direct Self‐Assembly of MXene on Zn Anodes for Dendrite‐Free Aqueous Zinc‐Ion Batteries

“…Impressively, such voltage hysteresis is also superior to most of previously reported anodes of ZIBs with different coating layers due to ultrathin thickness and unique structure of MXene layer (Figure 3 f). [2,12,13] The higher kinetics of MZn-60 over pure Zn is also confirmed by cyclic voltammogram (CV) tests in Zn/Ti half cells (Figure 3 d). The initial potentials of Zn plating/stripping are À0.063/0.034 V for MZn-60, while the corresponding initial potentials of pure Zn appear at À0.072/0.056 V, indicating the decreased overpotentials of Zn anode with the aid of MXene layer.…”

An In‐Depth Study of Zn Metal Surface Chemistry for Advanced Aqueous Zn‐Ion Batteries

“…Building artificial solid-electrolyte interphase (SEI) layers should be a good alternative, which could not only inhibit Zn dendrite growth, but also stop the side reactions. [11] The inhomogeneous and uncompacted artificial layers built by ex situ techniques, however, are unlikely to effectively block electrolyte from the Zn metal surface, and thus the side reactions, including Zn corrosion and hydrogen evolution, would still occur when the uncovered Zn contacted with the electrolyte. Even worse, such SEI layers feature poor adhesion and are easily detached from the Zn surface due to the volume changes during cycling, so they cannot fully protect the fresh Zn metal underneath.…”

Sandwich‐Like Heterostructures of MoS2/Graphene with Enlarged Interlayer Spacing and Enhanced Hydrophilicity as High‐Performance Cathodes for Aqueous Zinc‐Ion Batteries

“…In particular, aqueous Zn-ion batteries (AZIBs) have attracted significant attention, due to the relatively low electrode potential (−0.763 V vs standard hydrogen electrode), high theoretical capacity (5851 mA h cm −3 and 820 mA h g −1 ), natural abundance of resources, nontoxicity, and high water compatibility of the metallic Zn anode. [15][16][17][18][19][20][21][22][23][24] However, the wide-scale application of AZIBs is limited by either unsatisfactory practical capacity or inferior cycling life resulting from the sluggish diffusion kinetics of divalent Zn 2+ in the host frameworks, dissolution of cathode materials, and dendrite growth on Zn. [25][26][27][28][29][30] The use of neutral or mildly acidic aqueous electrolytes can reportedly improve the cycling stability of Zn anodes.…”