In-situ construction of dynamic Zn2+ rectification interfacial layer to regulate Zn2+ kinetics and oriented Zn deposition for aqueous Zinc-Ion batteries

Despite the widely acknowledged and remarkable advantages of aqueous zinc-ion batteries (ZIBs), issues such as uncontrollable dendrite growth and hydrogen evolution reaction, which severely affect their rechargeable stability and cycle life. To address these issues, a dynamic Zn 2+ ions rectification interfacial layer (DRIL) was constructed via in-situ spin coating and crosslinking of hydrophilic borax-modified hydroxypropyl guar gum on the Zn anode (BHPG@Zn). During the process of in-situ crosslinking, BHPG formed a carded molecular chain structure through synergistic crosslinking with borax, which re-regulated the uniform distribution of Zn 2+ ion fluxes at the interface. Leveraging the abundant oxygen-containing functional groups on BHPG, the inherent strong hydrogen-bonding network environment formed by water molecules is disrupted through strong coupling with Zn 2+ ions, thus promoting the transportation and desolvation of Zn 2+ ions. Furthermore, the stronger binding energy and affinity between BHPG and zinc induce the formation of a (002) plane-oriented Zn deposition layer. Based on the DRIL modification, the BHPG@Zn displays stable cycling for over 7100 h at 2 mA cm −2 with coulombic efficiency of 99.3 %, while the AC@Ti||BHPG@Zn zinc-ion capacitor retains a capacity of 65 mAh g −1 after 10,000 cycles at 2 A g −1 .