Zinc-based batteries offer a safe, inexpensive alternative to fire-prone lithium-based batteries, yet have been historically limited by poor rechargeability. A 3D zinc (Zn) “sponge” electrode architecture was developed comprising interpenetrating networks of Zn scaffolding and void space. The design characteristics yield superior electrochemical properties when cycled in alkaline electrolytes compared to conventional Zn powder-composite electrodes.
The longstanding problem of dendrite formation upon cycling is solved by distributing current more homogeneously in 3D throughout the electrode volume, while the void structure constrains dissolution/precipitation processes within the electrode. This breakthrough transforms the future capabilities and performance of the entire family of Zn-based alkaline batteries. By swapping in the 3D Zn sponge for traditional powdered or foil Zn anodes, fully rechargeable nickel-zinc prototype cells were demonstrated that challenge Li-ion performance, but that use aqueous-based cell chemistry that is inherently safer than the non-aqueous liquids used in Li batteries, thereby meeting the goal of a robust, energy-dense, safe battery.
The sponge features high charge-storage capacity (>90% of theoretical Zn specific capacity on single-discharge), supports high-power operation including under complex duty-cycle loads, and offers dendrite-free operation through extended charge-discharge cycling at deep levels of Zn utilization. The fused monolithic electrode structure can be molded to a desired form factor. Applications include primary (disposable) batteries, secondary (rechargeable) batteries, and 3D solid-state batteries.