Electrochemical Performance and Mechanism of Calcium Metal‐Organic Battery

Abstract

The abundance of Ca, its low redox potential and high specific capacity make Ca metal batteries an attractive energy storage system for the future. A recent demonstration of room temperature calcium plating/stripping opened a new avenue of the development, but the performance of cathode materials is lagging far behind. Due to the nature of divalent cations, conversion and coordination electrochemical reactions show better performance compared to insertion. Herein, we demonstrate the use of the anthraquinone‐based polymer as a cathode material for the Ca metal‐organic battery. Electrochemical mechanism investigation confirms the reversible reduction of the carbonyl bond and coordination with Ca2+ cations in the discharged state, opening a pathway toward high energy density battery. Continued performance of a 2‐electrode cell is strongly hampered by the overpotential increase caused by the Ca stripping process on the Ca metal anode stating the need for further development of Ca electrolytes. Ca metal‐organic battery promises to achieve cells with gravimetric energy density on the practical level compared to the state‐of‐the‐art Li‐ion batteries.

Spectroscopic Insights into the Electrochemical Mechanism of Rechargeable Calcium/Sulfur Batteries

“…46 There are however in fairly good agreement with the galvanostatic profile recently reported by Li et al, 51 confirming the low overpotential for stripping of calcium in alkoxyborate-based electrolyte. 47,48,52 The initiation of the subsequent charge starts at well-defined potential at approximately 2.4 V vs.…”

“…Reversible calcium deposition and stripping at room temperature was confirmed by 3-electrode electrochemical test with several types of working electrodes. 52 Carbon/sulfur composite obtained by sulfur impregnation of activated carbon cloth are widely used electrodes for investigating emerging metal/sulfur batteries. 35,[53][54][55] Here the impregnation process follows well-established protocols.…”

A Self‐Conditioned Metalloporphyrin as a Highly Stable Cathode for Fast Rechargeable Magnesium Batteries

“…The ratio significantly reduces (to below 1) upon discharging, which suggests the withdrawal of the anion in the discharging process. The presence of B in the fully discharged electrode possibly indicates a partial insertion of [MgB(hfip)4] + , [32] at least on the surface region. On the other hand, the N/Mg atomic ratio after 100 cycles decreases from around 1.5 in the charged state to almost 1 upon discharging, which suggests the introduction of the Mg ions in the discharging process.…”

Dielectric Hole Collector toward Boosting Charge Transfer of CsPbBr3 Hybrid Nanogenerator by Coupling Triboelectric and Photovoltaic Effects

“…[ 15,16 ] Many charge boosting strategies including air‐ion injection, [ 17 ] charge pumping, [ 18 ] and lowering the air pressure to vacuum [ 19 ] have been developed toward maximizing the surface charge density, but all the above approaches applied external injected charges passively rather than extracted charges from the source. In addition to mechanical energy, generators driven by solar, [ 20,21 ] thermal, [ 22,23 ] and chemical energies [ 24–26 ] are usually provided relatively high current outputs. In theory, the coupling of triboelectric effect with high current output characteristic could dramatically improve the electromechanical coupling coefficient as well as the charge extraction efficiency.…”