Thesis Title: Boosting zinc metal anodes performance via interface engineering: reaction kinetics, morphology control and electrochemical reversibility
Chief Supervisor: Dr ZHANG Biao
The thesis is devoted to reversible Zn metal anodes through regulating the Zn nucleation and growth. We first demonstrate that the slow desolvation kinetics elevates the nucleation overpotential for improving the nucleation sites through introducing acetonitrile co-solvent into the electrolyte. The electrolyte recipe is further tailored to produce abundant Zn nucleation seeds and smooth Zn growth. The designed oligomer co-solvent enables preferential surface adsorption and the optimized solvation sheath. Furthermore, we propose a facile pulsed cycling protocol where an initial high current density (J) is leveraged to form sufficient nuclei for guiding even metal deposition at standard J in the subsequent process, realizing high-performance Zn, Li and K metal batteries. Besides modulating the Zn nucleation, we also control the Zn growth process by constructing a metallic tin-coated separator. Specifically, its decent electrical conductivity and zincophilicity can eliminate the inevitably formed Zn dendrites via face-to-face Zn growth, thus enabling improved cycle life even at high J and cycling capacity.