This design provides a scalable route for in situ synthesizing of special carbon nanoscrolls as the cathode for an aluminum battery. The frizzy architectures are generated by a few graphene layers convoluting into the hollow carbon scroll, possessing rapid electronic transportation channels, superior anion storage capability, and outstanding ability of accommodating a large volume expansion during the cycling process. The electrochemical performance of the carbon nanoscroll cathode is fully tapped, displaying an excellent reversible discharge capacity of 104 mAh g at 1000 mA g. After 55 000 cycles, this cathode retains a superior reversible specific capacity of 101.24 mAh g at an ultrafast rate of 50 000 mA g, around 100% of the initial capacity, which demonstrates a superior electrochemical performance. In addition, anionic storage capability and structural stability are discussed in detail. The battery capacity under a wide temperature range from -80 to 120 °C is examined. At a low temperature of -25 °C, the battery delivers a discharge capacity of 62.83 mAh g after 10 000 cycles, obtaining a capacity retention near 100%. In addition, it achieves a capacity of 99.5 mAh g after 4000 cycles at a high temperature of 80 °C, with a capacity retention close to 100%. The carbon nanoscrolls possess an outstanding ultrafast charging/variable discharging rate performance surpassing all the batteries previously reported, which are highly promising for being applied in energy storage fields.

Large-scale low cost synthesis methods for potassium ion battery (PIB) anodes with long cycle life and high capacity has remained challenging. Here, inspired by the structure of a biological cell, biomimetic carbon cells (BCCs) were synthesized and used as PIB anodes. The protruding carbon nanotubes across the BCC wall mimicked the ion transporting channels present in the cell membrane, and enhanced the rate performance of PIBs. In addition, the robust carbon shell of the BCC could protect its overall structure, and the open space inside the BCC could accommodate the volume changes caused by K+ insertion, which greatly improved the stability of PIBs. For the first time, a stable SEI layer is formed on the surface of amorphous carbon. Collectively, the unique structural characteristics of the BCCs resulted in PIBs that showed a high reversible capacity (302 mAh g–1 at 100 mA g–1 and 248 mAh g–1 at 500 mA g–1), excellent cycle stability (reversible capacity of 226 mAh g–1 after 2100 cycles and a continuous running time of more than 15 months at a current density of 100 mA g–1), and an excellent rate performance (160 mAh g–1 at 1 A g–1). This study represents a new strategy for boosting the battery performance, and could pave the way for the next generation battery-powered applications.

Reasonable design of Sb-based nanomaterials, which can alleviate volume expansion, agglomeration and pulverization, is meaningful for PIBs.

Particulate 6092-T6 Al metal matrix composites ͑MMCs͒ reinforced with 20 vol % of B 4 C, SiC, and Al 2 O 3 exhibited localized corrosion when immersed in a 0.5 M Na 2 SO 4 solution exposed to air at room temperature. For the MMCs reinforced with B 4 C and SiC, the scanning vibrating electrode technique ͑SVET͒ revealed that corrosion initiated at localized anodic regions, which transformed into cathodic regions over time. The scanning ion-selective electrode technique ͑SIET͒ revealed that the localized anodic regions were acidified, and the localized cathodic regions were alkalinized. The observed anodic-cathodic transformation behavior was attributed to aluminum which has amphoteric oxides, the formation of microcrevices by reinforcement particles left in relief, and the possible galvanic action between the 6092-T6 Al matrix and the B 4 C and SiC reinforcement particles. The localized anodic and cathodic regions were many times larger than the individual reinforcement particle size. For the Al 2 O 3 -reinforced MMC, localized corrosion coincided with regions showing some cathodic activity and alkalinity. The extent of corrosion of these three MMCs was found to increase with decreasing reinforcement resistivities ͑i.e.

Graphene is of great significance in energy storage devices. However, a graphene-based electrode is difficult to use in direct applications due to the large surface area and flexibility, which leads to the excessive consumption of electrolyte, low Coulombic efficiency, and electrode shedding behaviors. Herein, a special crystal carbon@graphene microsphere (CCGM) composite was successfully synthesized. The scalable carbonaceous microsphere composite displays a small specific surface area and a superior structure stability. As a potassium ion battery electrode in a half-cell, CCGM delivers an initial capacity of 297.89 mAh g −1 with a high Coulombic efficiency of about 99%. It achieves an excellent cyclic stability with no capacity loss after 1250 cycles at the low current density of 100 mA g −1 with a long performing period of more than one year. As the cathode for an aluminum battery, a reversible specific capacity of 99.1 mAh g −1 at 1000 mA g −1 is obtained. CCGM delivers a long cycle performance of about 10 000 cycles at 4000 mA g −1 with a capacity retention of nearly 100%. Our design provides a fresh thought for the improvement of graphene-based materials, and it will greatly facilitate the application of graphene in the field of energy storage.