Ultrastrong bioinspired “brick-and-mortar” artificial SEI for dendrite-free Zn anode

Dendrite growth in Zn anodes poses a significant challenge for Zn-ion batteries, limiting their practical application. Current approaches using artificial solid electrolyte interphase (SEI) layers struggle to improve mechanical strength and ion transport simultaneously. Inspired by the "brick-and-mortar" microstructure model of natural shells, we engineered a robust bioinspired interfacial layer (BIL) to cap the anode and succeeded in inhibiting dendrite growth. The BIL exhibits a high Young’s modulus of 9.8 GPa, which flattens the depositional growth of Zn on the anode. Equally importantly, the ion conductivity in the presence of the BIL achieves 2.1 mS cm⁻¹, sufficient to meet the required ion transfer. When evaluated in symmetric Zn cells, the BIL enables steady cyclic operation for 2,500 h at 1 mA cm⁻² with 1 mAh cm⁻². Remarkably, at a limited amount of Zn as a BIL-protected anode in a Zn||MnO₂ full cell, the discharge capacity remains at 132 mAh g⁻¹ after 550 cycles.