An Encapsulation-Based Zn Electroplating/Stripping via 3D Hollow PPy

Abstract

Zn dendrite growth in aqueous electrolyte greatly shorten the cycle life of zinc ion hybrid supercapacitor (ZHS). However, conventional physical modification layers and electrode structure designs cannot buffer the large volume changes during Zn deposition and stripping. Herein, we design and construct 3D hollow polypyridine (PPy) framework to achieve the deposition and growth of Zn metal on the inner wall of hollow PPy foam. We explore the deposition patterns of Zn within 3D PPy and find electroplating/stripping behavior depend on the limitation of metallic Zn within 3D PPy. This behavior avoids dendrite problem, improves the reversibility of the battery, and achieves an average coulomb efficiency (CE) of 99% for 150 cycles. The ZHS assembled with Zn@PPy and AC exhibits stable cycles over 10,000 times with near 100% CE and capacity retention ratio at 50% DODZn. Importantly, this strategy provides new insights and ideas for solving the Zn anode dendrite problem.