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An aluminum‐ion battery was assembled with potassium nickel hexacyanoferrate (KNHCF) as a cathode and Al foil as an anode in aqueous electrolyte for the first time, based on Al3+ intercalation and deintercalation. A combination of ex situ XRD, X‐ray photoelectron spectroscopy (XPS), galvanostatic intermittent titration technique (GITT), and differential capacity analysis was used to unveil the crystal structure changes and the insertion/extraction mechanism of Al3+. Al3+ could reversibly insert/extract into/from KNHCF nanoparticles through a single‐phase reaction with reduction/oxidation of Fe and Ni. Over long‐term cycling, it was Fe rather than Ni that contributed to more capacity owing to the dissolution of Ni from the KNHCF structure, which could be expressed as a compensation effect of mixed redox centers in KNHCF. KNHCF delivered an initial discharge capacity of 46.5 mAh g−1. The capacity decay could be attributed to the unstable interface between Al foil and the aqueous electrolyte owing to the catalytic activity of the Ni transferring from Ni dissolution of KNHCF to the Al foil anode, rather than KNHCF structure collapse; KNHCF maintained its 3 D framework structure for 500 cycles. This work is expected to inspire more exhaustive investigations of the mechanisms that occur in aluminum‐ion batteries.

Carbonized Zn-(Metal-Organic Framework)MOF-polyaniline composites for high performance of supercapacitor have been developed from zinc acetate, 8-Hydroxyquinoline, and aniline via a simple process. The as-synthesized product has been characterized by X-ray powder diffraction (XRD), Scanning electron microscopy(SEM), Fourier transform infrared spectra (FT-IR), Transmission electron microscope (TEM). The electrochemical properties of carbonized Zn-MOF/polyaniline electrode were investigated by current charge-discharge and cyclic voltammetry. The specific capacitance of MOF/PANI has been approach to be as high as 477 F g-1 at a current density of 1A g-1 .

Hard carbon (HC) has become one of the prospective anode materials for sodium-ion batteries (SIBs), but its application suffers from the low electron conductivity and poor ion-diffusion kinetics. In this study, the melting and evaporation process of neutral salt was first introduced to produce nitrogen-rich interpenetrated porous HC (NIP-HC) as the anode for SIBs. Such a protocol allows for the first-demonstrated porous structure for HC materials with desired electronic conductivity and much improved rate performance than the conventional porous structure. As a result, high reversible capacity (358 mA h g–1) and enhanced rate property (239.8 mA h g–1 at 2 A g–1) are achieved with improved electrode kinetics and electron conductivity because of the accelerated charge transfer derived from the unique porosity and nitrogen heteroatom-doping. More interestingly, the increase of the surface area of NIP-HC does not lead to a decrease of the initial efficiency. At the same time, a high plateau capacity (172.8 mA h g–1) can be obtained below 0.1 V, which shows great potential for practical application in the full cells. As suggested by IG/ID from Raman tests, the degree of graphitization increases accompanied by the melting and evaporation process, which improves the electrical conductivity of the HC material as well. Furthermore, according to first-principle calculations, it is found that the nitrogen is conducive to increasing the electron density around the Fermi level, which intrinsically enhances the electrical conductivity and enriches active sites for sodium-ion storage. The result from this study has provided insights into producing interpenetrated porous HC by a simple and novel salt melting and evaporation process and enriched the methods of pore structure preparation.

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