A Novel Aluminum‐Ion Battery: Al/AlCl₃‐[EMIm]Cl/Ni₃S₂@Graphene

Abstract

may offer noteworthy cost saving and safety improvement compared to its counterparts. Additionally, aluminum has a very negative redox potential (≈1.676 V vs standard hydrogen electrode (SHE)) and a small electrochemical equivalent (0.336 g Ah −1 ), which make it one of the ideal elements for rechargeable batteries. However, the previous efforts have encountered numerous issues over the past few years, such as the cathode material disintegration, [12,14] low discharge voltage, [8] capacitive behavior without discharge voltage plateaus. [15,16] There is no doubt that some of recent works have explored a series of new electrode materials, such as V 2 O 5 , [8] TiO 2 , [9] fluorinated natural graphite, [15] polymers, [16] and Prussian blue analogues (PBAs). [12] The previous work has revealed that Al ions can insert into TiO 2 nanotube arrays and PBAs in aqueous solution. But the discharge capacity of these materials is too low. Very recently, the works from our group at University of Science and Technology Beijing (USTB) and Dai and co-workers at Stanford University found that rechargeable aluminum-ion batteries using graphite materials cathode had a very high charge/discharge voltage plateau around 2.0 V versus Al 3+ /Al. [12,17] The charge/discharge reaction happens through the intercalation and deintercalation of AlCl 4 − into interlayer space of graphite materials.Herein, we report for the first time, the design of Ni 3 S 2 / graphene microflakes composite as a novel cathode material for rechargeable aluminum-ion batteries. The battery runs through the electrochemical deposition and dissolution of aluminum at the anode, and the intercalation and deintercalation of Al 3+ cations in the cathode. The unique advantage of Ni 3 S 2 /graphene microflakes composite lies in the low charge-transfer impedance, which represents a high rate of intercalation and deintercalation of ions. Additionally, we find that there is a dissociation process of Al 2 Cl 7 − during charge process, and the active material transforms from monocrystal to polycrystal at the same time. The battery exhibits a high discharge voltage plateau (≈1.0 V vs Al/AlCl 4 − ), a discharge capacity of over 60 mA h g −1 , a high coulombic efficiency of about 99% , and a high rate capability, suggesting that it is a favorable cathode material for high-performance aluminumion batteries.

Graphene: A Cathode Material of Choice for Aluminum‐Ion Batteries

“…[67] Similar behaviors could also be observed for Ni 3 S 2 and CuS. [10,12,13,17,[64][65][66][67] Although it is reported that V 2 O 5 delivers specific capacity of 273 mAh g À1 ,i ti sb asically attributed to the side reactions. [37] None of the other cathodes could attain such high specific capacity nor sustain such high current rate.…”

“…[10-13, 17, 36, 41-43, 46, 47, 49, 50, 64-67] Indeed, most of the cathodes, irrespective of compositions,d isplay am iserable discharge voltage plateau at approximately 0.5-0.6 V( vs. Al). [13,65] Graphene has the ability to deliver specific capacities as high as 148 mAh g À1 (at current density of 2Ag À1 ). [67] Similar behaviors could also be observed for Ni 3 S 2 and CuS.…”

“…[8,[12][13][14][15][16][17] Ac omprehensive analysis of various cathodes and electrolytes within the realm of AIBs was discussed in ap revious Review. [8,[12][13][14][15][16][17] Ac omprehensive analysis of various cathodes and electrolytes within the realm of AIBs was discussed in ap revious Review.…”

Self‐Supported Tin Sulfide Porous Films for Flexible Aluminum‐Ion Batteries

“…On the other side, the XPS spectra of sulfur present a similar shift in the pristine, discharged, and charged states. [7,20,24,26,27] It is noted that this is the first time to find the variations of metallic and sulfur valence state in one AIBs system. [20] Similarly, after charging, the spectra of sulfur recovered to the pristine state with a higher binding energy increasing, revealing that a reversible reaction increases the valence state of sulfur.…”

Low‐Cost Metallic Anode Materials for High Performance Rechargeable Batteries

“…More information of those aqueous AIBs could be found in the recent elaborated review by Elia et al [88] AIBs in non-aqueous electrolytes have attracted much more attention in recent years because of the higher working voltage as well as higher energy density. [92] Typically, the non-aqueous electrolytes possess a general formula of MCl-AlCl 3 (M + = Li + , Na + , K + , or organic cations like pyrrolidinium or imidazolium). These electrolytes are defined to be basic, neutral or acid when the ratio of MCl/AlCl 3 >1, = 1, and <1, respectively.…”