Efficient Aluminum Chloride–Natural Graphite Battery

Abstract

The quest for low-cost and large-scale stationary storage of electricity has led to a surge of reports on novel batteries comprising exclusively highly abundant chemical elements. Aluminum-based systems, inter alia, are appealing because of the safety and affordability of aluminum anodes. In this work, we examined the recently proposed aluminum–ionic liquid–graphite architecture. Using 27Al nuclear magnetic resonance, we confirmed that AlCl4 – acts as an intercalating species. Although previous studies have focused on graphitic cathodes, we analyzed the practicality of achievable energy densities and found that the AlCl3-based ionic liquid is a capacity-limiting anode material. By focusing on both the graphitic cathode and the AlCl3-based anode, we improved the overall energy density. First, high cathodic capacities of ≤150 mAh g–1 and energy efficiencies of 90% at high electrode loadings of at least 10 mg cm–2 were obtained with natural, highly crystalline graphite flakes, which were subjected to minimal mechanical processing. Second, the AlCl3 content in the ionic liquid was increased to its maximal value, which essentially doubled the energy density of the battery, resulting in a cell-level energy density of ≤62 Wh kg–1. The resulting batteries were also characterized by high power densities of at least 489 W kg–1.

Rechargeable Dual‐Ion Batteries with Graphite as a Cathode: Key Challenges and Opportunities

“…As described by Kravchyk et al, [96] sonication can preserve the GF and CP of the graphite, which contrasts with other mechanical top-down processes, such as ball-milling which partially amorphize the material. 2019, 9,1901749 [96] Copyright 2017, The American Chemical Society. Likely, this perfection also remains after they are broken into smaller sizes.…”

“…Therefore, the anion intercalation proceeds into graphite through different Adv. [96] Copyright 2017, The American Chemical Society. 2019, 9,1901749 1 and 2, accordingly).…”

“…As indicated in the work of Kravchyk et al [96] the electrochemical performance of large natural graphite flakes can be further improved by their processing into smaller GF, for instance, by sonication. As indicated in the work of Kravchyk et al [96] the electrochemical performance of large natural graphite flakes can be further improved by their processing into smaller GF, for instance, by sonication.…”

Perspective—State of the Art of Rechargeable Aluminum Batteries in Non-Aqueous Systems

“…Gifford et al described this novel battery system in 1988 with aluminum and graphite as the negative and positive electrodes respectively, in a Lewis acidic chloroaluminate ionic liquid at room temperature. Chloroaluminate anions intercalated into the graphite electrode reaching 64 Wh kg −1 specific energy at 1.7 V discharge voltage over 150 cycles and 80-90% coulombic efficiency.2 The same idea was taken up several years later by various research groups 1,[3][4][5] …”

“…Chloroaluminate anions intercalated into the graphite electrode reaching 64 Wh kg −1 specific energy at 1.7 V discharge voltage over 150 cycles and 80-90% coulombic efficiency. 2 The same idea was taken up several years later by various research groups 1,[3][4][5] using different oxides, sulfides and zeolites materials as intercalation electrodes. [6][7][8][9][10][11][12][13] More recently the introduction of conductive polymers (CP) as intercalation electrode sets a further development with great potential for a rechargeable aluminum hybrid battery-capacitor energy storage system.…”