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Stable Sodium-Metal Batteries in Carbonate Electrolytes Achieved by Bifunctional, Sustainable Separators with Tailored Alignment.

Published version
Peer-reviewed

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Abstract

Sodium (Na) is the most appealing alternative to lithium as an anode material for cost-effective, high-energy-density energy-storage systems by virtue of its high theoretical capacity and abundance as a resource. However, the uncontrolled growth of Na dendrites and the limited cell cycle life impede the large-scale practical implementation of Na-metal batteries (SMBs) in commonly used and low-cost carbonate electrolytes. Herein, the employment of a novel bifunctional electrospun nanofibrous separator comprising well-ordered, uniaxially aligned arrays, and abundant sodiophilic functional groups is presented for SMBs. By tailoring the alignment degree, this unique separator integrates with the merits of serving as highly aligned ion-redistributors to self-orientate/homogenize the flux of Na-ions from a chemical molecule level and physically suppressing Na dendrite puncture at a mechanical structure level. Remarkably, unprecedented long-term cycling performances at high current densities (≥1000 h at 1 and 3 mA cm-2 , ≥700 h at 5 mA cm-2 ) of symmetric cells are achieved in additive-free carbonate electrolytes. Moreover, the corresponding sodium-organic battery demonstrates a high energy density and prolonged cyclability over 1000 cycles. This work opens up a new and facile avenue for the development of stable, low-cost, and safe-credible SMBs, which could be readily extended to other alkali-metal batteries.

Description

Funder: Edinburgh Napier University; Id: http://dx.doi.org/10.13039/501100001292


Funder: China Scholarship Council; Id: http://dx.doi.org/10.13039/501100004543

Keywords

carbonate electrolytes, highly aligned nanofibers, long cycle life, sodium-metal batteries, sustainable separators

Journal Title

Adv Mater

Conference Name

Journal ISSN

0935-9648
1521-4095

Volume Title

Publisher

Wiley
Sponsorship
Engineering and Physical Sciences Research Council (EP/V002651/1)