Polyporphyrin-Modified Hierarchical Framework Interface Layer Facilitates Highly Stable Microcrystallized Surface for Zn Anode.

Abstract

In recent years, aqueous Zn-ion batteries have gained significant development due to their advantages of low cost, high safety, and high theoretical capacity. However, their commercialization has been much hindered by the serious dendrite growth and low Coulombic efficiency of Zn electrodes. To address these challenges, a strategy for surface modifying carbon nanotube sponge with polyindium porphyrin (POF-S) is systematically designed and prepared as the multifunctional interface layer for Zn anode. As verified by theoretical calculations and tests, POF-S possesses both hierarchical pore structures and regularly arranged Zn affinity centers. The advantages of organic and inorganic on modulating interfaces are thus effectively combined in POF-S to inhibit dendrite growth, suppress side reaction, and boost high interfacial stability of the Zn anode. The observable influence of the POF-S interface layer promotes the microcrystallized dense deposition, which manifests in two forms of zinc (Zn₍₀₀₂₎ + Zn₍₁₀₁₎) on the anode. The thermodynamic advantages of the Zn₍₀₀₂₎ layer extend the cycling lifespan of the Zn anode to 5000 h under the condition of 1 mA cm^-2/1 mAh cm^-2. And the epitaxial growth advantage of Zn₍₁₀₁₎ makes the electrode capable of maintaining interface stability under larger current (20 mA cm^-2) and deeper charge/discharge (10 mAh cm^-2). Furthermore, the POF-S@Zn//MnO₂ full battery can maintain a specific capacity of more than 120 mAh g^-1 after 2200 cycles at a current of 2 A g^-1.