Sustainability and Technical Performance of An All‐Organic Aqueous Sodium‐Ion Hybrid Supercapacitor

Abstract

Development of all‐organic aqueous energy storage devices (ESDs) is a promising pathway towards meeting the needs of technically medium/low‐demanding electrical applications. Such ESDs should favour low cost, low environmental impact, and safety, and thereby complement more expensive, high voltage, and energy/power dense ESDs such as lithium‐ion batteries. Herein, we set out to assemble all‐organic aqueous Na‐ion hybrid supercapacitors, exclusively using commercial materials, with the aim to provide a truly sustainable and low‐cost ESD. Overall, the created ESD delivers adequate technical performance in terms of capacity retention, Coulombic efficiency, energy efficiency, and energy/power density. Finally, we apply a straight‐forward and qualitative biodegradability method to the ESD.

Le Chatelier's principle enables stable and sustainable aqueous sodium/magnesium-ion batteries

“…This could be due to either: (i) the use of a high power performant anode, not acting as a bottle neck, and/or (ii) the lower electrolyte concentration (<5 m vs. $17 m), generating lower viscosity and higher ionic conductivity, and therefore allowing for faster charging/discharging rates. Furthermore, the active material level energy density (35 W h kg −1 PTCDA+Mn-PBA at 0.2C) is more than twice that of our previous PTCDAjAC hybrid supercapacitor device (17 W h kg −1 PTCDA+AC ), 19 and similar to previously reported PBA-based ASIBs (Fig. 4b), 11,12,32,33,35,[38][39][40] while simultaneously retaining a very good power density (1700 W kg −1 PTCDA+Mn-PBA at 50C)highlighting Mn-PBA's cathode material capability for both energy and power, and its tting electrochemical traits with PTCDA.…”

“…Sodium sulfate (Na 2 SO 4 ) (anhydrous, Redi-Dri™, free-owing, ACS reagent, $99%), magnesium sulfate (MgSO 4 ) (anhydrous, free-owing, Redi-Dri™, ReagentPlus®, $99.5%), and manganese(II) sulfate monohydrate (MnSO 4 $H 2 O) (ReagentPlus®, $99%), all purchased from Sigma-Aldrich, were used to create the electrolytes. The hybrid electrolyte (1.9 m Na 2 SO 4 + 2.4 m MgSO 4 ), 17,19 and the triple electrolyte (1.9 m Na 2 SO 4 + 2.4 m MgSO 4 + 0.3 m MnSO 4 ) were both prepared by rst dissolving Na 2 SO 4 to saturation in ultra-pure water (Millipore® Direct-Q® Purication, 18.2 MU cm at 25 °C), before adding MgSO 4 , and for the latter nally also MnSO 4 , all in magnetically stirred vials at ca. 50 °C.…”

“…We choose PTCDA rather than the more commonly used NaTi 2 (PO 4 ) 3 (NTP), 18 due to its commercial availability, cycling stability, and high power performance. 19 We start by studying the active charge carrier(s) and the electrode cycling reversibility by basic electrochemical and ex situ material characterization methods, respectively, followed by electrochemical characterization of Mn-PBA in half-cells with the hybrid and triple electrolytes. Finally, we assemble full cells of PTCDAjMn-PBA and evaluate their functionality.…”

Is “Water in Salt” Electrolytes the Ultimate Solution? Achieving High Stability of Organic Anodes in Diluted Electrolyte Solutions Via a Wise Anions Selection

“…demonstrated a beneficial combination of MgSO 4 (2.4 m) dissolved in saturated aqueous Na 2 SO 4 solution (1.9 m) to get an improved performance of PTCDA. Despite the enhanced stability enabled by this hybrid electrolyte, the capacity of the PTCDA electrode was about half of what is obtained in organic electrolytes [18] (70 vs. ≈135 mAh/g) while a fluctuating columbic efficiency of ranges between 94 % to 99 % was observed during 100 cycles [19] . Considering the above, we present herein stably operating PTCDA anodes in diluted (1 M) sodium ion based electrolyte solutions by careful selection of the electrolyte anions.…”

“…Despite the enhanced stability enabled by this hybrid electrolyte, the capacity of the PTCDA electrode was about half of what is obtained in organic electrolytes [18] (70 vs. � 135 mAh/g) while a fluctuating columbic efficiency of ranges between 94 % to 99 % was observed during 100 cycles. [19] Considering the above, we present herein stably operating PTCDA anodes in diluted (1 M) sodium ion based electrolyte solutions by careful selection of the electrolyte anions. We demonstrate that a careful selection of chaotropic (water structure breakers) anions (particularly ClO 4 À ( enables the impressive performance of PTCDA anodes even in very diluted electrolyte solutions comprising 0.2 M NaClO 4 .…”