Disordered, Large Interlayer Spacing, and Oxygen‐Rich Carbon Nanosheets for Potassium Ion Hybrid Capacitor

Abstract

Potassium ion storage technology as a promising substitute for the well‐developed lithium ion storage technology is still at the infancy stage of development, and exploring suitable electrode materials is critical for its practical application. Here, the great feasibility of disordered, large interlayer spacing, and oxygen‐rich carbon nanosheets (CNSs) prepared by chemical vapor deposition for potassium ion storage applications is demonstrated. As an anode material, the CNSs exhibit outstanding rate capability as well as excellent cyclic stability. Taking advantage of this, a potassium ion hybrid capacitor (PIHC) is constructed by employing such CNSs as the battery‐type anode and activated carbon as the capacitor‐type cathode. The resulting device displays a high energy density of 149 Wh kg−1, an ultrahigh power output of 21 kW kg−1, as well as a long cycling life (80% capacity retention after 5000 cycles), which are all close to the state‐of‐the‐art values for PIHCs. This work promotes the development of high‐performance anode material for potassium ion storage devices, and the designed PIHC pushes the energy density and power density to a higher level.

All‐Printed MnHCF‐MnOx‐Based High‐Performance Flexible Supercapacitors

“…The cycle stable performance was measured by CT2001A battery test system. The electrode capacitance was calculated by GCD curves according to the following equation: [ 53–55 ] …”

“…The cycle stable performance was measured by CT2001A battery test system. The electrode capacitance was calculated by GCD curves according to the following equation: [53][54][55] In the devices, the areal capacitance was also obtained by GCD curves according to the following equation:…”

Constructing Multichannel Carbon Fibers as Freestanding Anodes for Potassium‐Ion Battery with High Capacity and Long Cycle Life

“…Figure 4a and Figure S3a-c (Supporting Information) exhibit the cyclic voltammetry (CV) curves of the MCCF electrodes at a scan rate of 0.1 mV s −1 for the initial five cycles. [36][37][38] The unsharp peaks below 0.4 V demonstrate the intercalation process of K + into MCCFs. [36][37][38] The unsharp peaks below 0.4 V demonstrate the intercalation process of K + into MCCFs.…”

“…All the CV curves show a broad reduction peak located at ≈1.4 V only in the first cycle, which should correspond to the formation of the solid electrolyte interface film due to the decomposition of the electrolyte and other side reactions. [36][37][38] The unsharp peaks below 0.4 V demonstrate the intercalation process of K + into MCCFs. [12] Correspondingly, the oxidation peaks located at around 0.3 and 0.7 V indicate the extraction of K + from the MCCF electrode.…”

Confined Metal Sulfides Nanoparticles into Porous Carbon Nanosheets with Surface‐Controlled Reactions for Fast and Stable Lithium‐Ion Batteries

“…To address these issues, one effective strategy is to integrate TMCs with conductive carbon matrixes, which can not only dramatically buffer the volume variation, but also improve the electronic conductivity and mechanical stability of anode materials, thus leading to the improved electrochemical performance in LIBs. [10,[15][16] Furthermore, the electrochemical reactions occurring on the surface could speed up charge/ion transfer to provide abundant pseudocapacitance. [11,[17][18][19] It is well known that the surface reaction contribution is related to the microstructure of the electrode.…”