Electrochemical Mechanism of Al Metal–Organic Battery Based on Phenanthrenequinone

Abstract

Al metal-organic batteries are a perspective high-energy battery technology based on abundant materials. However, the practical energy density of Al metal-organic batteries is strongly dependent on its electrochemical mechanism. Energy density is mostly governed by the nature of the aluminium complex ion and utilization of redox activity of the organic group. Although organic cathodes have been used before, detailed study of the electrochemical mechanism is typically not the primary focus. In the present work, electrochemical mechanism of Al metal-phenanthrenequinone battery is investigated with a range of different analytical techniques. Firstly, its capacity retention is optimized through the preparation of insoluble cross-coupled polymer, which exemplifies extremely low capacity fade and long-term cycling stability. Ex situ and operando ATR-IR confirm that reduction of phenanthrenequinone group proceeds through the two-electron reduction of carbonyl groups, which was previously believed to exchange only one-electron, severely limiting cathode capacity. Nature of aluminium complex ion interacting with organic cathode is determined through multiprong approach using SEM-EDS, XPS, and solid-state NMR, which all point to the dominant contribution of AlCl2+ cation. Upon full capacity utilization, Al metal-polyphenanthrenequinone battery utilizing AlCl2+ offers an energy density of more than 200 Wh/kg making it a viable solution for stationary electrical energy storage.

H2‐Inhibited Organic Anodes for Fast and Long‐Life Aqueous Aluminum Ion Batteries with a 3.5‐Month Calendar Life

“…Furthermore, the gradually intensified Al signal (Figure 3e) reveals the successful electrochemical storage of Al by PI‐0.6. [ 42 ] The restored O 1s peaks (Figure 3d) and the disappeared Al signal after charging (Figure 3e) clearly certifies the high reversibility.…”

Constructing NiCo2Se4/NiCoS4 heterostructures for high-performance rechargeable aluminum battery cathodes

“…6 Among these post-LIBs, rechargeable aluminum batteries (RABs) have been regarded as a replacement for LIBs because aluminum (Al) is the most abundant metal in the Earth's crust (82 000 ppm for Al), and it has ultrahigh theoretical volumetric capacities (8035 mA h cm −3 ) and theoretical gravimetric capacities (2980 mA h g −1 ). 7 Inspired by Dai's research that designed RABs comprising graphitic-foam cathodes, Al anodes, and [EMIm]Al x Cl y ionic liquid electrolytes, 8 more and more research on cathode materials for aluminum batteries has been carried out, mainly concentrating on carbon-based materials, [9][10][11][12][13][14][15] organic molecules, [16][17][18][19] oxides, [20][21][22] sulfides, [23][24][25] selenides, [26][27][28][29][30] and tellurides. 31 Nonetheless, the development of cathode materials has encountered some challenging issues.…”

Ion storage performance of a polymer for mono-, di- and tri-valent metal ions in non-aqueous electrolytes

“…Though there are several studies on organic electrodes for LIBs, reports showing reversible and stable performance of ZIBs and AIBs using organic electrodes are limited. 5–12…”

“…Though there are several studies on organic electrodes for LIBs, reports showing reversible and stable performance of ZIBs and AIBs using organic electrodes are limited. [5][6][7][8][9][10][11][12] Organic electrodes including small molecules, conducting polymers, radical polymers, organosulfur and conjugated carbonyl compounds, covalent organic frameworks (COFs), and metal organic frameworks (MOFs) have been widely reported in non-aqueous LIBs. 6,7 The non-aqueous ZIBs are of particular interest due to extended potential windows of operation in addition to dendrite-free chemistry.…”