3D zincophilic micro-scaffold enables stable Zn deposition

Abstract

Aqueous zinc ion battery is a promising technology for safe and low-cost energy storage. However, zinc batteries using metallic Zn anode suffer from poor cycle life due to Zn dendrites growth, side reactions and parasitic byproducts. To tackle these issues, we design a potent Zn anode host by combining two strategies, a 3D microporous scaffold and zincophilic surfaces. This design proves advantageous in stabilizing Zn metal deposition and improving the cycle life of full cells. Specifically, a Sn nanodots coated porous carbon fiber (Sn-PCF) network has been carefully designed. The PCF network is conducive in promoting homogeneous Zn2+ flux and uniform 3D Zn nucleation, leading to dense and flat Zn deposition even under a high capacity of 10 mAh cm−2. Meanwhile, experiments and calculation reveal that, the Sn nanodots coating induces a strongly zincophilic surface of each fiber with high Zn2+ adsorption and surface immobilization. This guarantees a high reversibility of Zn plating/stripping compared to PCF without Sn coating or other non-3D hosts. The advantage of this 3D Sn-PCF host is demonstrated in both symmetric cells and full device paired with Na2V6O16 cathode.