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.

In this study, we established a rechargeable aluminum ion super battery with high-rate capability using a low temperature inorganic molten salt which is much cheaper, safer and environmentally friendly.

An ultrafast rechargeable multi-ions battery is presented, in which multi-ions can electrochemically intercalate into graphite layers, exhibiting a high reversible discharge capacity of ≈100 mAh g and a Coulombic efficiency of ≈99% over hundreds of cycles at a high current density. The results may open up a new paradigm for multi-ions-based electrochemical battery technologies and applications.

Issues with the dissolution and diffusion of polysulfides in liquid organic electrolytes hinder the advance of lithium-sulfur batteries for next-generation energy storage. To trap and re-utilize the polysulfides without hampering lithium ion conductivity, a bio-inspired, brush-like interlayer consisting of zinc oxide (ZnO) nanowires and interconnected conductive frameworks is proposed. The chemical effect of ZnO on capturing polysulfides has been conceptually confirmed, initially by using a commercially available macroporous nickel foam as a conductive backbone, which is then replaced by a free-standing, ultra-light micro/mesoporous carbon (C) nanofiber mat for practical application. Having a high sulfur loading of 3 mg cm −2 , the sulfur/ multi-walled carbon nanotube composite cathode with a ZnO/C interlayer exhibits a reversible capacity of 776 mA h g −1 after 200 cycles at 1C with only 0.05% average capacity loss per cycle. A good cycle performance at a high rate can be mainly attributed to the strong chemical bonding between ZnO and polysulfides, fast electron transfer, and an optimized ion diffusion path arising from a well-organized nanoarchitecture. These results herald a new approach to advanced lithium-sulfur batteries using brush-like chemi-functional interlayers.

Producing graphene through the electrochemical reduction of CO2 remains a great challenge, which requires precise control of the reaction kinetics, such as diffusivities of multiple ions, solubility of various gases, and the nucleation/growth of carbon on a surface. Here, graphene was successfully created from the greenhouse gas CO2 using molten salts. The results showed that CO2 could be effectively fixed by oxygen ions in CaCl2-NaCl-CaO melts to form carbonate ions, and subsequently electrochemically split into graphene on a stainless steel cathode; O2 gas was produced at the RuO2-TiO2 inert anode. The formation of graphene in this manner can be ascribed to the catalysis of active Fe, Ni, and Cu atoms at the surface of the cathode and the microexplosion effect through evolution of CO in between graphite layers. This finding may lead to a new generation of proceedures for the synthesis of high value-added products from CO2, which may also contribute to the establishment of a low-carbon and sustainable world.