A Pyramidal Metal-Organic Frameworks-Derived FeP@CoP Aluminium-Ion Battery Cathode Displaying Low-Temperature Tolerance and Fast Electron Transfer Kinetics.

Anhui Provincial Engineering Laboratory for Engineering appropriate cathode materials is significant for the development of high-performance aluminum-ion (Al-ion) batteries. Here, a pyramidal metal-organic frameworks (MOFs)-derived FeP@CoP composite was developed as cathode, which exhibits good stability and high capacity. FeP@CoP cathode maintains a high capacity of 168 mAh g-1 after 200 cycles, and displays a stable rate-performance at both room and low temperatures of -10 °C. After three rounds of rate-performance cycling, the FeP@CoP composite recovers 178.2 mAh g-1 at 0.3 A g-1 . Moreover, density functional theory (DFT) calculations verify improved electron-transfer kinetics with narrowed band gap and enhanced density of states. These findings inspire a broad set of studies on MOFs-derived composites for high-performance secondary batteries.

Rational engineering NiMoO4nanosheets or Mn3O4nanowires on Fe2O3microdiscs as novel hierarchical anodes for high-performance lithium-ion batteries.

Since current graphite-based lithium-ion battery anode has a low theoretical capacity, the development of high-performance lithium-ion battery is severely restricted. Here, novel hierarchical composites composing of microdisc and the secondarily grown nanosheets and nanowires are developed, taking NiMoO4nanosheets and Mn3O4nanowires growing on Fe2O3microdiscs as demonstrating examples. The growth processes of the hierarchical structures have been investigated by adjusting a series of preparation conditions. The morphologies and structures have been characterized by using scanning electron microscopy, transmission electron microscope and x-ray diffraction. Fe2O3@Mn3O4composite-based anode displays a capacity of 713 mAh g-1after 100 cycles at 0.5 A g-1with a high Coulombic efficiency. A good rate-performance is also achieved. Fe2O3@NiMoO4anode delivers 539 mAh g-1after 100 cycles at 0.5 A g-1, which is obviously higher than that of pure Fe2O3. The hierarchical structure is conducive to improve the transport of electrons and ions, and provide numerous active sites, thus significantly enhancing the electrochemical performance. Moreover, the electron transfer performance is investigated by using density functional theory calculations. It is expected the findings presented here and the rational engineering of nanosheets/nanowires on microdiscs would be applicable for developing many other high-performance energy-storage composites.

A nanowire-on-microrod polyaniline@FeS2 hybrid as the cathode in high-performance Al-ion batteries.

A nanowire-on-microrod structured polyaniline (PANI)@FeS2 hybrid was developed via a facile metal-organic framework (MOF)-derived chemical method. The in situ grown PANI nanowires on the surface of pyramidal FeS2 microrods displayed better mechanical flexibility and improved Al-storage performance. The PANI nanowires not only enhanced electron transfer during the electrochemical reaction, but also accommodated the volume expansion of FeS2 during discharge. The PANI@FeS2 hybrid as the cathode in AIBs delivered a reliable battery capacity of 152.8 mA h g-1 along with a Coulombic efficiency of >96.5% after 500 cycles at a current density of 1.5 A g-1. In addition, a high capacity retention of 160.2 mA h g-1 after 150 cycles at 0.5 A g-1 at -10 °C was achieved. These findings provide a feasible strategy by constructing a nanowire-on-microrod hybrid that can be applied in high-performance secondary batteries.

A metal organic framework-derived octahedral Cu1.95S@CoS2 for secondary batteries displaying long cycle life and stable temperature tolerance.

Low-cost and safe batteries are considered to be promising energy-storage systems. Here, a metal organic framework (MOF)-derived octahedral Cu1.95S@CoS2 composite is developed as a high-performance cathode of aluminium-ion (Al-ion) batteries. CoS2 nanoparticles on Cu1.95S provide active sites, making AlCl4- intercalation/deintercalation highly reversible, and reducing polarization. Cycling at 0.5 A g-1, Cu1.95S@CoS2 maintains stable capacities of 136.6 and 122.4 mA h g-1 after 200 cycles at room temperature and -10 °C, respectively. Stable rate-performance is also achieved. These findings will accelerate the application of Al-ion batteries and MOF-derived energy-storage composites.

A lamellar V2O3@C composite for aluminium-ion batteries displaying long cycle life and low-temperature tolerance.

Rechargeable aluminum-ion (Al-ion) batteries have important potential for fast charging and safe energy-storage systems. Here, we develop a composite composed of lamellar V2O3@C nanosheets, which displays high electrochemical properties as an Al-ion battery cathode. The unique structure is conducive to the rapid insertion and release of Al3+ ions, electrolyte infiltration, and improved conductivity. After cycling 500 times, the capacity exceeds 242.5 mA h g-1. Under a low temperature of -10 °C, the capacity remains 150.8 mA h g-1, and the Coulombic efficiency is higher than 98.8%. The V2O3@C also exhibits a good reversibility verified by using ex situ X-ray powder diffraction patterns, while the constant current intermittent titration technology shows a low reaction barrier, which indicates that the lamellar composite presented here could find significant applications for engineering many high-performance energy-storage systems.