Highly Durable and Stable Sodium Superoxide in Concentrated Electrolytes for Sodium–Oxygen Batteries,Advanced Energy Materials

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Highly Durable and Stable Sodium Superoxide in Concentrated Electrolytes for Sodium–Oxygen Batteries
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2018-10-16 , DOI: 10.1002/aenm.201801760
Hyeokjun Park _{1,

2} , Jinsoo Kim ₃ , Myeong Hwan Lee ₁ , Sung Kwan Park ₁ , Do-Hoon Kim _{1,

2} , Youngjoon Bae _{1,

2} , Youngmin Ko _{1,

2} , Byungju Lee ₁ , Kisuk Kang _{1,

2}

Affiliation

Rechargeable sodium–oxygen batteries have attracted considerable interest as promising candidates for next‐generation batteries owing to their large energy density, high energy efficiency, and potential cost‐effectiveness. The intrinsic stability of the discharge product, sodium superoxide, results in highly reversible solution‐based electrochemistry in sodium–oxygen batteries, leading to their higher energy efficiency and reversibility compared with their lithium counterparts. However, recent studies have shown that extended storage of sodium superoxide in ethereal electrolytes induces dissolution of the sodium superoxide and undesirable chemical reactions with the electrolytes, resulting in significant degradation of the cell reversibility. In this study, the use of high‐concentration electrolytes is explored to obstruct the dissolution of sodium superoxide and to suppress parasitic reactions during storage of sodium–oxygen batteries. Unique solvated structures are identified with the elimination of free solvents through systematic investigations using controlled electrolyte concentrations. Time‐resolved ex situ characterizations reveal that sodium superoxide stored in concentrated electrolyte exhibits far greater stability and prolonged lifetime than that stored in conventional electrolytes. It is finally demonstrated that the highly durable sodium superoxide in the concentrated electrolyte succeeds in preserving both the high energy efficiency and oxygen reversibility of sodium–oxygen batteries even with long rest periods every cycle.

中文翻译：

用于钠氧电池的浓缩电解质中的高度耐用和稳定的过氧化钠

可充电钠氧电池由于其高能量密度，高能效和潜在的成本效益而成为下一代电池的有前途的候选者，引起了广泛的关注。放电产物内在的稳定性，即过氧化钠，导致钠氧电池中基于溶液的高度可逆的电化学反应，与锂同类电池相比，具有更高的能效和可逆性。但是，最近的研究表明，在醚性电解质中延长过氧化钠的储存会引起过氧化钠的溶解和与电解质的不良化学反应，从而导致电池可逆性的显着降低。在这项研究中，探索了使用高浓度电解质来阻止过氧化钠的溶解并抑制钠氧电池在储存过程中的寄生反应。通过使用受控电解质浓度的系统研究，可以消除游离溶剂，从而鉴定出独特的溶剂化结构。时间分辨的异位表征表明，与传统电解质相比，浓电解质中存储的过氧化钠具有更高的稳定性和更长的使用寿命。最终证明，即使在每个循环中有较长的休息时间，浓电解质中高度耐用的超氧化钠也能成功保持钠氧电池的高能效和氧可逆性。

更新日期：2018-10-16

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