Tailoring interfacial Zn2+ coordination via a robust cation conductive film enables high performance zinc metal battery

Targeted Delivery of Zinc Ion Derived by Pseudopolyrotaxane Gel Polymer Electrolyte for Long-Life Zn Anode

“…On account of the intrinsic properties, rechargeable aqueous zinc ion battery (ZIB) is considered as the promising candidate for the stationary energy storage system. − Zn metal can serve as the anode of ZIB in aqueous electrolyte due to its high theoretical capacity of 5833 mAh cm –2 , the tolerance of water and oxygen, the low potential (−0.76 V vs standard hydrogen electrode), as well as environmental friendliness. − Recently, decent electrochemical performance of cathode has been achieved in ZIBs. − The reaction mechanisms of the cathodes such as the manganese-based compounds, vanadium-based compounds, Prussian blue analogues, and organic compounds have been also investigated, which advance the development of ZIBs. − However, the Zn anode is prone to suffer from the issue of Zn dendrite, which is originated from the uneven Zn plating. − As illustrated in Figure a, owing to the limited Zn 2+ transport, large amounts of zinc ion accumulate at the anode/electrolyte interface . Zinc ion is apt to plate on the location of the Zn anode which presents the minimized surface energy in aqueous electrolyte.…”

Diminishing Space-Charge Layer Effect of Zinc Anodes by an Anion-Immobilized Electrolyte Membrane

“…In this theory, anions are expelled from the metal electrode and accumulated near the counter electrode during the metal deposition process, which creates an anion-depleted boundary and electric field at the metal electrode/electrolyte interface. Such a space-charge region is generally accepted to be another important inducement of dendrites formation. , Accordingly, Archer et al proposed a novel concept of anion immobilization by introducing ionic liquid–nanoparticle components with tethered anions into liquid electrolytes, and the in-depth theoretical modeling results revealed that immobilizing even a small proportion of anions (10%) would substantially promote the electrodeposition stability. , To date, the strategy of constructing an anion immobilization interface has become an significant guideline for the suppression of Li dendrite growth. − Although tethered anionic sites in various organic materials, including Nafion, , polyanionic polymers, , and SPEEK, , have been demonstrated to be coordinated with Zn 2+ cations to rectify ion transport, the space-charge layer effect induced by free anions in a conventional aqueous electrolyte is usually overlooked.…”

Hydrogels Enable Future Smart Batteries

“…First, the polymers with high shear modulus and appropriate stiffness on the anode have been successfully applied to suppress the metal dendrite growth. , Second, the hydrogel polymer networks can make ion flux in the bulk uniform and induce lateral ion flux near the interface, which can be helpful in regulating the metal ion deposition in a homogeneous way and avoiding dendrite formation. Moreover, by introducing polyanions into the polymer network, such as a carboxylate group (−COO – ) , and sulfonate group (−SO 3 – ), − the ion-confinement capability in the hydrogel electrolyte may restrict the movement of cations and further stabilize the metal anode. These hydrogel strategies in aqueous batteries are equally applicable to ionogels in non-aqueous batteries, such as lithium and sodium batteries …”