Biomimetic shunt effects to simultaneously regulate solvation and interface structure for high-performance Zn metal anode

High-safety aqueous zinc (Zn) ion batteries confront hydrogen evolution reaction (HER) and dendrite growth of Zn anode, which can be well solved by electrolyte optimization and electrode modification. However, the simultaneously implementation of the electrolyte solvation structure and electrode/electrolyte interface regulation has been ignored and rarely investigated. In this work, inspired by shunt mechanism of hemicellulose in plant kingdom, xylan (XL) was designed and developed as a trace electrolyte additive (ZS@XL) to disperse in aqueous electrolyte and adsorb on Zn anode to simultaneously regulate solvation structure and electrode/electrolyte interface of Zn anode. XL-adsorbed layer can act as "shunt channels" to uniform ion flux and physical barrier to reduce the contact between active H2O and Zn metal, thus suppressing dendrite growth and HER. Meanwhile, high binding energy of XL with Zn2+ can destroy the solvation structure of Zn(H2O)62+ to decrease the number of active H2O and facilitate fast desolvation kinetics for the hindrance of HER. As a result, Zn anode with ZS@XL achieves excellent plating/stripping reversibility of 1400 cycles, long cycling life of 2800 h, as well as Zn-iodine (I2) full battery with ZS@XL exhibits excellent cycling performance of 16,000 cycles and practical application to power electric instruments. This work opens a novel route to simultaneously regulate electrolyte solvation structure and electrode/electrolyte interface of Zn anode by biomass materials.