Sodiophilic Amyloid Fibril Modified Separator for Dendrite-Free Sodium Metal Batteries.

Sodium (Na) batteries are being considered as prospective candidates for the next generation of secondary batteries in contrast to lithium-based batteries, due to their high raw material abundance, low cost, and sustainability. However, the unfavorable growth of Na metal deposition and severe interfacial reactions have prevented their large-scale applications. Here we propose a vacuum filtration strategy through amyloid fibril modified glass fiber separators to address these issues. The modified symmetric cell can be cycled for 1800 h, surpassing the performance of previously reported Na-based electrodes under an ester-based electrolyte. Moreover, the Na/ Na 3 V 2 (PO 4 ) 3 full cell with a sodiophilic amyloid fibril modified separator exhibits a capacity retention of 87.13% even after 1000 cycles. Both experimental and theoretical results show sodiophilic amyloid fibril homogenizes electric field and Na ion concentration, fundamentally inhibiting dendrite formation. Simultaneously, the glutamine amino acids in the amyloid fibril have the highest adsorption energy for Na, resulting in the formation of a stable Na 3 N and NaN x O y -rich solid electrolyte interface film on the anode during cycling. This work provides not only a possible pathway to solve dendrite problem in metal batteries using environmental-friendly biomacromolecular materials, but also a new direction for expanding biomaterial applications. This article is protected by copyright. All rights reserved.