Mechanistic Study of Interfacial Modification for Stable Zn Anode Based on a Thin Separator

Abstract

The interface plays a pivotal role in stabilizing metal anode. Extensive studies have been made but systematic research is lacking. In this study, preliminary studies are conducted to explore the prime conditions of interfacial modification to approach the practical requirements. Critical factors including reaction kinetics, transport rate, and modulus are identified to affect the Zn anode morphology significantly. The fundamental principle to enhance the Zn anode stability is systematically studied using the TEMPO‐oxidized cellulose nanofiber (TOCNF) coating layer with thin a separator. Its advantageous mechanical properties buffer the huge volume variation. The existence of hydrophilic TOCNF in the Zn anode interface enhances the mass transfer process and alters the Zn2+ distribution with a record high double‐layer capacitance (390 uF cm−2). With the synergetic effect, the modified Zn anode works stably under 5 mA cm−2 with a thin nonwoven paper as the separator (thickness 113 µm). At an ultra‐high current density of 10 mA cm−2, this coated anode cycles for more than 300 h. This strategy shows an immense potential to drive the Zn anode forward toward practical applications.

Construction of zwitterionic osmolyte-based hydrogel electrolytes towards stable zinc anode for durable aqueous zinc ion storage and integrated electronics

“…In general, the Zn ions in LE tend to 2D diffuse along the Zn anode surface to find the energetically favorable sites (tip sites) for diminishing the surface energy, and then the Zn 2+ ions aggregate together and further are reduced into dendrites. 13,56 As for the SPS–Zn system, the current density remains stable after 60 s, suggesting that the initial nucleation and transverse diffusion processes occurred in a relatively short time followed by steady and constant three-dimensional (3D) diffusion. The obtained results indicated that SPS–Zn can constrain the 2D surface lateral movement and facilitate the absorbed Zn 2+ ions on the electrode to locally reduce into metallic Zn (as illustrated in Fig.…”

Ultra‐Stable Zn Anode Enabled by Fiber‐Directed Ion Migration Using Mass‐Producible Separator

“…[ 14 ] However, these conventional materials cannot fully satisfy the requirements of a high performance separator, including low thickness, high porosity, sufficient mechanical strength, high electrolyte wettability, and low cost. [ 10,15 ] Meanwhile, these materials can hardly induce the uniform distribution and deposition of Zn 2+ , resulting in low Coulombic efficiencies, poor cyclability, and premature device failure. [ 13b ]…”

Improved Strategies for Separators in Zinc‐Ion Batteries

“…Li et al. proposed a facile and distinct interfacial engineering strategy to immobilize persimmon branch carbon (PBC) material on a cellulose filter (CF) paper separator [55] . The PBC material with graded pore structure, uniformly distributed carbon sites, and abundant N and O functional groups is designed as an effective ion transport modulator PBC@CF separator with the dual functions of facilitating ion transfer and inhibiting dendrite growth.…”