A Hybrid Na//K ⁺ -Containing Electrolyte//O ₂ Battery with High Rechargeability and Cycle Stability

Abstract

<jats:p>Na-O<jats:sub>2</jats:sub> and K-O<jats:sub>2</jats:sub> batteries have attracted extensive attention in recent years. However, the parasitic reactions involving the discharge product of NaO<jats:sub>2</jats:sub> or K anode with electrolytes and the severe Na or K dendrites plague their rechargeability and cycle stability. Herein, we report a hybrid Na//K<jats:sup>+</jats:sup>-containing electrolyte//O<jats:sub>2</jats:sub> battery consisting of a Na anode, 1.0 M of potassium triflate in diglyme, and a porous carbon cathode. Upon discharging, KO<jats:sub>2</jats:sub> is preferentially produced via oxygen reduction in the cathode with Na<jats:sup>+</jats:sup> stripped from the Na anode, and reversely, the KO<jats:sub>2</jats:sub> is electrochemically decomposed with Na<jats:sup>+</jats:sup> plated back onto the anode. The new reaction pathway can circumvent the parasitic reactions involving instable NaO<jats:sub>2</jats:sub> and active K anode, and alternatively, the good stability and conductivity of KO<jats:sub>2</jats:sub> and stable Na stripping/plating in the presence of K<jats:sup>+</jats:sup> enable the hybrid battery to exhibit an average discharge/charge voltage gap of 0.15 V, high Coulombic efficiency of &gt;96%, and superior cycling stability of 120 cycles. This will pave a new pathway to promote metal-air batteries.</jats:p>

A Two‐Dimensional Metal–Organic Polymer Enabled by Robust Nickel–Nitrogen and Hydrogen Bonds for Exceptional Sodium‐Ion Storage

“…[8][9][10][11] Concentrated electrolytes also function to mitigate the dissolution of organic electrode materials or synergistically optimize the interfacial structure. [12][13][14] However,t hough the low electrical conductivity of organic electrode materials can be enhanced by the addition or in combination of carbons,t he large amount of inactive carbon compromises their large specific capacities.I ti sh ighly imperative to design stable organic compounds with multiple redox centers and high intrinsic electron conduction for good electrochemical performance.…”

A Two‐Dimensional Metal–Organic Polymer Enabled by Robust Nickel–Nitrogen and Hydrogen Bonds for Exceptional Sodium‐Ion Storage

“…Rational design of the organic electrode materials, including moiety modification and polymerization of the active small molecules, has been extensively applied to promote the electrochemical performance [8–11] . Concentrated electrolytes also function to mitigate the dissolution of organic electrode materials or synergistically optimize the interfacial structure [12–14] . However, though the low electrical conductivity of organic electrode materials can be enhanced by the addition or in combination of carbons, the large amount of inactive carbon compromises their large specific capacities.…”

“…[8][9][10][11] Concentrated electrolytes also function to mitigate the dissolution of organic electrode materials or synergistically optimize the interfacial structure. [12][13][14] However,though the low electrical conductivity of organic electrode materials can be enhanced by the addition or in combination of carbons,t he large amount of inactive carbon compromises their large specific capacities.I ti sh ighly imperative to design stable organic compounds with multiple redox centers and high in-trinsic electron conduction for good electrochemical performance.…”

Strategies Toward Stable Nonaqueous Alkali Metal–O2 Batteries

“…[72] A sodiated carbon, which is widely studied as anode material for Na-and K-ion batteries with high capacity, [73] showed high stability without dendrite formation in a Na-O 2 cell (Figure 8c,d). [79] This hybrid battery was operated based on reversible KO 2 redox reaction in the cathode while maintaining Na stripping/platting in the anode, thus eliminated the parasitic reactions of unstable NaO 2 and active K anode. [75] In addition, alloy was demonstrated as a potential candidate for inhibiting dendrite growth in alkali metal batteries and may also be effective in metal-O 2 batteries.…”

“…The alloy–O 2 battery was capable of 137 cycles with a CNT cathode and 250 cycles with a modified RuO 2 /CNT cathode in the TEGDME‐based electrolyte, significantly higher than the Na or Li anode alone (< 40 cycles). By synthetically considering the parasitic reactions involving the NaO 2 in Na–O 2 battery and the K anode in K–O 2 battery, Li's group subtly designed a hybrid battery containing a metallic Na anode and K + based electrolyte . This hybrid battery was operated based on reversible KO 2 redox reaction in the cathode while maintaining Na stripping/platting in the anode, thus eliminated the parasitic reactions of unstable NaO 2 and active K anode.…”