Graphene Armored with a Crystal Carbon Shell for Ultrahigh-Performance Potassium Ion Batteries and Aluminum Batteries

Abstract

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.

Cucurbit[6]uril‐Derived Nitrogen‐Doped Hierarchical Porous Carbon Confined in Graphene Network for Potassium‐Ion Hybrid Capacitors

“…The XRD patterns (Figure 2c) of CBC and CBC@G exhibit two broad peaks at about 25° and 43°, assigned to the (002) and (101) planes of the graphite crystal, respectively. [ 35,36 ] Notably, the slightly right‐shifted diffraction angle of the (002) plane (inset of Figure 2c) of CBC@G reveals a slightly narrower interlayer spacing than that of CBC, and the interlayer spacing of CBC@G and CBC calculated by Bragg's Law are 0.350 and 0.355 nm, respectively. The deviation of the carbon interlayer spacing calculated based on the lattice fringes and XRD may be due to the amorphous characteristics of cucurbit[6]uril‐derived carbon.…”

Electrochemical Fixation of Carbon Dioxide in Molten Salts on Liquid Zinc Cathode to Zinc@Graphitic Carbon Spheres for Enhanced Energy Storage

“…[ 26,27 ] In this regard, pioneering works were conducted by Lu and co‐workers. [ 7,28–33 ] In their strategy, a highly porous 3D graphene foam is used as the cathode for rechargeable Al‐ion batteries, enabling a high capacity of ≈123 mAh g −1 at 5 A g −1 , a high Coulombic efficiency of more than 98%, and a long‐term stability up to 10 000 cycles as well as a high rate performance. [ 28 ] Also, Gao and co‐workers designed a special “trihigh tricontinuous” graphene film cathode, presenting a high capacity of ≈120 mAh g −1 at an ultrahigh current density of 400 A g −1 .…”

Synthesis of Porous Proton Ion Conducting Solid Polymer Blend Electrolytes Based on PVA: CS Polymers: Structural, Morphological and Electrochemical Properties

“…Different approaches including polymer blending and using various salts were investigated to overcome the poor conduction of PE systems. As mentioned in the literature, inorganic salts, particularly alkali metal salts, can significantly improve the conductivity of SPEs and make them reliable for many energy device applications, such as lithium-ion batteries and dual-ion capacitors [22][23][24][25][26]. PVA is a semicrystalline polymer with many hydroxyl functional groups attached to its backbone structure.…”