Polyimides as Promising Cathodes for Metal–Organic Batteries: A Comparison between Divalent (Ca²⁺, Mg²⁺) and Monovalent (Li⁺, Na⁺) Cations

Abstract

Ca-and Mg-based batteries represent a more sustainable alternative to Liion batteries. However, multivalent cation technologies suffer from poor cation mass transport. In addition, the development of positive electrodes enabling reversible charge storage currently represents one of the major challenges. Organic positive electrodes, in addition to being the most sustainable and potentially low-cost candidates, compared with their inorganic counterparts, currently present the best electrochemical performances in Ca and Mg cells. Unfortunately, organic positive electrodes suffer from relatively low capacity retention upon cycling, the origin of which is not yet fully understood. Here, 1,4,5,8naphthalenetetracarboxylic dianhydride-derived polyimide was tested in Li, Na, Mg, and Ca cells for the sake of comparison in terms of redox potential, gravimetric capacities, capacity retention, and rate capability. The redox mechanisms were also investigated by means of operando IR experiments, and a parameter affecting most figures of merit has been identified: the presence of contact ion-pairs in the electrolyte.

Supramolecular Engineering of Ti3C2Tx MXene ‐Perylene Diimide Hybrid Electrodes for the Pseudocapacitive Electrochemical Storage of Calcium Ions

“…However, bulk organic electrodes are known to exhibit diffusion-controlled redox processes, which suffer from poor rate and cycling performance. [57] At potentials above −0.1 V versus Ag/AgCl, both Ti 3 C 2 T x and Ti 3 C 2 T x @cPDI exhibit double-layer charging, giving rise to intercalation capacitance. The representative cyclic voltammograms from 5 to 100 mV s −1 are shown in Figure 4b.…”

Current Trends and Perspectives of Polymers in Batteries

“…Redox polymers are also known for the versatility of their redox chemistry and the possibility of using different ions from Li and Na including multivalent ions such as Mg, Ca, or Al to organics. For instance, several redox polymers including catechol, polyimides, or phenothiazine have recently been demonstrated as universal hosts for aqueous rechargeable batteries based on mono-, di-, or trivalent cations. − As two seminal examples of the possibilities of using multivalent ions, an ultrahigh performance zinc–organic battery using a poly­(catechol) cathode in concentrated aqueous electrolytes was recently shown by Marcilla and co-workers, and Esser et al demonstrated recently an aluminum–organic battery …”

Calcium Cosalt Addition to Alter the Cation Solvation Structure and Enhance the Ca Metal Anode Performance

“…To meet society’s growing needs for renewable energy storage, novel battery chemistries with higher energy density and lower cost than Li-ion batteries need to be developed. , Ca metal batteries have been proposed as alternatives to Li-ion batteries due to the greater crustal abundance (41,500 mg/kg for Ca vs 20 mg/kg for Li) and anode capacity (1337 mAh/g for Ca metal anodes vs 372 mAh/g for Li/C 6 anodes). Despite these advantages, development of Ca metal batteries has been limited. ,− …”