Constructing an In Situ Polymer Electrolyte and a Na-Rich Artificial SEI Layer toward Practical Solid-State Na Metal Batteries

Abstract

Sodium is one of the most promising anode candidates for the beyond-lithium-ion batteries. The development of Na metal batteries with a high energy density, high safety, and low cost is desirable to meet the requirements of both portable and stationary electrical energy storage. However, several problems caused by the unstable Na metal anode and the unsafe liquid electrolyte severely hinder their practical applications. Herein, we report a facile but effective methodology to construct an in situ polymer electrolyte and Na-rich artificial solid-electrolyte interface (SEI) layer concurrently. The obtained integrated Na metal batteries display long cycling life and admirable dynamic performance with total inhibition of dendrites, excellent contact of the cathode/polymer electrolyte, and reduction of side reactions during cycling. The modified Na metal electrode with the in situ polymer electrolyte is stable and dendrite-free in repeated plating/stripping processes with a life span of above 1000 h. Moreover, this method is compatible with different cathodes that demonstrate outstanding electrochemical performance in full cells. We believe that this approach provides a practical solution to solid-state Na metal batteries.

Wide-temperature-range sodium-metal batteries: from fundamentals and obstacles to optimization

“…Therefore, as a strategy, construction of an artificial SEI protective layer through spontaneous reactions can effectively improve the cycling performance of SMBs. 84,394 Differently, some active materials with sodophilic properties, such as Te, V and Sn, are dispersed within sodium metal using a simple method of repeated cold rolling and folding. 140,395,396 The thermodynamically stable structure is encapsulated within sodium metal, which facilitates the state-of-the-art electrochemical properties.…”

“…Therefore, as a strategy, construction of an artificial SEI protective layer through spontaneous reactions can effectively improve the cycling performance of SMBs. 84,394…”

In situ-fabricated quasi-solid polymer electrolytes incorporating an ionic liquid for flexible supercapacitors

“…20–22 For instance, various epoxides, such as ethylene oxide and 1,3-dioxopentane, and acrylate/methacrylate monomers/oligomers have been tested for in situ polymerization. 23–25 Especially, the strong polarity of the CO bond in these candidates is always conductive to the formation of long chain segments during polymerization, enhancing the ionic-migration efficiency and conductivity. These effective strategies have thus attracted widespread attention in the field of secondary batteries but relatively less notice in SCs.…”

Suppression of Dendrites by a Self-Healing Elastic Interface in a Sodium Metal Battery

“…In terms of the separator, for example, the porosity gradient was structured in a gel polymer electrolyte to alleviate the growth of sodium dendrite . On the sodium metal anode, − an antimony triiodetetrahydrofuran (THF) solution was used to in-situ construct an antimony-based lithium interphase on the dendrite-free lithium anode. As for the electrolyte, it is very crucial to design a stable Na/electrolyte interface, and so an ultra-high concentration ceramic ionic conductor is used to build the ion conduction “highway”. − But the problem with the sodium dendrite still needs to be further explored.…”