Work

Molecular Hydrogen Governs Zinc-Based Battery Failure

Year: 2026

Type: preprint

Abstract: Zinc is among the most promising anode materials for sustainable aqueous batteries, yet its practical deployment is limited by poor interfacial stability and insufficient durability. Because the thermodynamic stability of zinc is incompatible with the water stability window, corrosion and hydrogen evolution inevitably accompany zinc electrochemistry in aqueous electrolytes. Despite being an inherent product of zinc corrosion, molecular hydrogen (H2) has largely been regarded as a passive by-product rather than an active contributor to zinc degradation and dendrite formation. Here, we demonstrate that H2 directly governs zinc deposition and stripping across multiple length scales. By combining operando fibre-optic surface plasmon resonance, electrochemical quartz crystal microbalance, X-ray diffraction and operando optical microscopy, we resolve the influence of H2 on the zinc–electrolyte interface from interfacial processes to macroscopic deposit growth. Dissolved H2 destabilizes zinc electrodeposition by increasing the plating overpotential and altering deposition dynamics. It induces a crystallographic texture transition from the basal (002) to the prismatic (101) orientation, producing more porous deposits and modifying the growth kinetics of the zinc deposition front. Quantitative optical-flow analysis further reveals that H2 accelerates local growth dynamics and increases interfacial roughness, thereby compromising deposition uniformity. These effects persist across different electrolyte chemistries and current densities, establishing molecular hydrogen as an active regulator of zinc interfacial stability. Consequently, H2 reduces the cycling lifetime of zinc symmetric cells and promotes premature short circuits in Zn–MnO2 batteries. These findings identify molecular hydrogen as a previously overlooked driver of the morphological and crystallographic evolution of zinc deposits and establish hydrogen management as a design principle for stabilizing the zinc–electrolyte interface. Controlling dissolved H2, including through electrolyte degassing strategies, therefore provides a route towards suppressing dendritic growth, extending battery lifetime and enabling more durable aqueous zinc batteries.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15008306/v1

Authors: Hugo Chotard, Murugasenapathi N K, Özlem Sel, Frédéric Kanoufi, Jean-Marie Tarascon, Ivette Aguilar