Boosting de-solvation via halloysite nanotubes-cellulose composite separator for dendrite-free zinc anodes

Abstract

Aqueous zinc-ion batteries (ZIBs) have attracted considerable attention owing to intrinsic advantages, which encompass inherent safety and a cost-effective manufacturing process. Nevertheless, the lifespan of Zn anodes is limited by inclement dendrite growth and adverse side reactions, impeding the commercial viability of ZIBs. In this study, we engineered a multifunctional cellulose-based separator (HC) synthesized from halloysite nanotubes (HNTs) and cellulose to address these challenges effectively. Leveraging the exceptional water adsorption capacity and the unique inner positive and outer negative tubular structure of HNTs molecules, the HC separator facilitates the de-solvation behavior of [Zn(H2O)6]2+ and promotes uniform deposition of Zn2+. Furthermore, the HC separator demonstrates superior wettability, excellent flexibility, and higher ionic conductivity, which further lead to dendrite-free zinc deposition, a 2700-h cycling lifespan, and a coulombic efficiency (CE) of 98.88 % after 100 cycles. Notably, the ZIBs incorporating the HC separator exhibit exceptional cycling performance, retaining 83.5 % of their capacity after 2000 cycles at 5 A g−1. This novel approach offers a valuable direction for the advancement of cost-effective and durable ZIBs.