锂氧电池利用高浓度的基于乙二醇的电解质,ACS Applied Energy Materials

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锂氧电池利用高浓度的基于乙二醇的电解质
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2020-11-30 , DOI: 10.1021/acsaem.0c02331
Vittorio Marangon ₁ , Celia Hernandez-Rentero ₂ , Stanislav Levchenko ₁ , Giacomo Bianchini ₁ , Davide Spagnolo ₁ , Alvaro Caballero ₂ , Julian Morales ₂ , Jusef Hassoun _{1,

3}

Affiliation

双（三氟甲磺酰基）酰亚胺锂（LiTFSI）和硝酸锂（LiNO ₃）的浓溶液）在二乙二醇二甲基醚（DEGDME）或三乙二醇二甲基醚（TREGDME）中的盐，鉴于其在锂氧电池中的电解质的可能应用，在化学和电化学性质上进行了表征。在锂电池中长时间存储后，锂金属表面的X射线光电子能谱揭示了通过还原溶液形成的固体电解质中间相（SEI）的复杂组成和性质，而热重分析显示了取决于糖链长度的稳定性。通过电化学阻抗谱（EIS），计时电流法，恒电流循环和伏安法研究了该溶液在锂金属电池中的适用性，揭示了两种电解质的高电导率和锂转移数以及宽的电化学稳定性窗口。然而，由于基于DEGDME的电解质相对于TREGDME的电解质蒸发更加明显，这是一个具有挑战性的问题，实际上限制了前者在Li / O中的应用_2块电池。因此，EIS测量表明，在长时间暴露于氧气气氛中时，使用基于DEGDME的电解质会大大提高电池的阻抗，这会导致相应的Li / O ₂电池性能下降。取而代之的是，使用基于TREGDME的电解液的电池表现出了显着的相间稳定性，并具有更大的响应速度，比容量范围为500至1000 mA hg ^–1（相对于正极碳质量），相关的最大实际能量密度为450 W千克^–1。这些结果表明，甘醇二甲醚的挥发性是允许在Li / O _2中使用电解质介质的决定因素。细胞。因此，使用沸点足够高的甘氨酸的电解质（例如TREGDME）会因存在相应的盐（包括保护锂的牺牲性锂盐（LiNO ₃））而进一步增加，从而可以安全安全地使用溶液。性能锂氧电池。

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Lithium–Oxygen Battery Exploiting Highly Concentrated Glyme-Based Electrolytes

Concentrated solutions of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate (LiNO₃) salts in either diethylene-glycol dimethyl-ether (DEGDME) or triethylene-glycol dimethyl-ether (TREGDME) are herein characterized in terms of chemical and electrochemical properties in view of possible applications as the electrolyte in lithium–oxygen batteries. X-ray photoelectron spectroscopy at the lithium metal surface upon prolonged storage in lithium cells reveals the complex composition and nature of the solid electrolyte interphase (SEI) formed through the reduction of the solutions, while thermogravimetric analysis shows a stability depending on the glyme chain length. The applicability of the solutions in the lithium metal cell is investigated by means of electrochemical impedance spectroscopy (EIS), chronoamperometry, galvanostatic cycling, and voltammetry, which reveal high conductivity and lithium transference number as well as a wide electrochemical stability window of both electrolytes. However, a challenging issue ascribed to the more pronounced evaporation of the electrolyte based on DEGDME with respect to TREGDME actually limits the application of the former in the Li/O₂ battery. Hence, EIS measurements reveal a very fast increase in the impedance of cells using the DEGDME-based electrolyte upon prolonged exposure to the oxygen atmosphere, which leads to a performance decay of the corresponding Li/O₂ battery. Instead, cells using the TREGDME-based electrolyte reveal remarkable interphase stability and much more enhanced response with specific capacity ranging from 500 to 1000 mA h g^–1 referred to the carbon mass in the positive electrode, with an associated maximum practical energy density of 450 W h kg^–1. These results suggest the glyme volatility as a determining factor for allowing the use of the electrolyte media in a Li/O₂ cell. Therefore, electrolytes using a glyme with sufficiently high boiling point, such as TREGDME, which is further increased by the relevant presence of salts including a lithium protecting sacrificial one (LiNO₃), can allow the application of the solutions in a safe and high-performance lithium–oxygen battery.

更新日期：2020-12-28

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