Simultaneous Regulation on Solvation Shell and Electrode Interface for Dendrite-Free Zn Ion Batteries: Achieved by a Low-Cost Glucose Additive.

Abstract

The dendrite growth and by-products in Zn metal aqueous batteries have impeded their fast development as promising energy storage devices. We hereby utilize a low-cost additive, glucose, to modulate the typical ZnSO4 electrolyte system for improving reversible plating/stripping on Zn anode for high-performance Zn ion batteries (ZIBs). Combing experimental characterizations and theoretical calculation in scales ranging from atom-level (sub-nanometer) quantum chemistry calculation, molecule-level (nanometer) ab-initio calculation and molecular dynamics simulations to macro-level (micrometer) finite element analysis, we prove that the glucose in ZnSO4 aqueous environment can simultanously modulate solvation structure of Zn2+ and Zn anode-electrolyte interface. The electrolyte engineering is capable of alternating one H2O molecule from the primary Zn2+-6H2O solvation shell and restraining side reactions due to the decomposition of active water. Concomitantly, glucose molecules are inclined to absorb on the surface of Zn anode, suppressing the random growth of Zn dendrite. As a proof of concept, symmetric cell and Zn-MnO2 full cell with glucose electrolyte achieve boosted stability than that with pure ZnSO4 electrolyte. These results pave a way to excavate cheap and high-efficient electrolyte engineering strategy for high-performance Zn-based devices.