Lightweight, Thin, and Flexible Silver Nanopaper Electrodes for High-Capacity Dendrite-Free Sodium Metal Anodes

Owing to its resource-abundant and favorable theoretical capacity, sodium metal is regarded as a promising anode material for sodium metal batteries. However, uncontrolled Na plating/stripping, including Na dendrite growth during cycling, has hindered its practical application. Herein, a sodiophilic, thin, and flexible silver nanopaper (AgNP) is designed based on interpenetrated nanocellulose and silver nanowires and is used as a dendrite-free Na metal electrode. Due to a network of highly conducting silver nanowire (0.6 Ω sq⁻¹, 8200 S cm⁻¹), the sodiophilic nature of silver, and the reduced internal strain within the flexible AgNP, a compact Na metal layer can be uniformly deposited on and reversibly stripped from the AgNP electrode without any observations of Na dendrites during cycling at 1 mA cm⁻² for 800 h. As the AgNP electrode is only 2 µm thick, with a low mass loading of 0.88 mg cm⁻², the AgNP–Na anode deposited with a Na deposition charge of 6 mAh cm⁻² exhibits a capacity of 995 mAh g⁻¹ _AgNP–Na, approaching that of a Na metal anode (1166 mAh g⁻¹ _Na). The present approach provides new possibilities for the development of lightweight and stable metal batteries.