Wang Huan, Wang Chuanlong, Matios Edward, Li Weiyang
Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire, 03755, USA.
Angew Chem Int Ed Engl. 2018 Jun 25;57(26):7734-7737. doi: 10.1002/anie.201801818. Epub 2018 May 25.
Sodium metal is an attractive anode for next-generation energy storage systems owing to its high specific capacity, low cost, and high abundance. Nevertheless, uncontrolled Na dendrite growth caused by the formation of unstable solid electrolyte interphase (SEI) leads to poor cycling performance and severe safety concerns. Sodium polysulfide (Na S ) alone is revealed to serve as a positive additive or pre-passivation agent in ether electrolyte to improve the long-term stability and reversibility of the Na anode, while Na S -NaNO as co-additive has an adverse effect, contrary to the prior findings in the lithium anode system. A superior cycling behavior of Na anode is first demonstrated at a current density up to 10 mA cm and a capacity up to 5 mAh cm over 100 cycles. As a proof of concept, a high-capacity Na-S battery was prepared by pre-passivating the Na anode with Na S . This study gives insights into understanding the differences between Li and Na systems.
由于具有高比容量、低成本和高丰度，金属钠是下一代储能系统中颇具吸引力的阳极材料。然而，由不稳定的固体电解质界面（SEI）形成导致的钠枝晶不受控制的生长会导致循环性能不佳以及严重的安全问题。单独的多硫化钠（Na₂Sₓ）被发现可作为醚类电解质中的正添加剂或预钝化剂，以提高钠阳极的长期稳定性和可逆性，而与锂阳极系统中的先前发现相反，Na₂Sₓ-NaNO₃作为共添加剂具有不利影响。首次证明了钠阳极在高达10 mA cm⁻²的电流密度和高达5 mAh cm⁻²的容量下经过100次循环具有优异的循环性能。作为概念验证，通过用Na₂Sₓ对钠阳极进行预钝化制备了高容量钠硫电池。这项研究为理解锂和钠系统之间的差异提供了见解。
