Preferential Pyrolysis Construction of Carbon Anodes with 8400 h Lifespan for High‐Energy‐Density K‐ion Batteries

Abstract

Carbonaceous materials are promising anodes for practical potassium‐ion batteries, but fail to meet the requirements for durability and high capacities at low potentials. Herein, we constructed a durable carbon anode for high‐energy‐density K‐ion full cells by a preferential pyrolysis strategy. Utilizing S and N volatilization from a π–π stacked supermolecule, the preferential pyrolysis process introduces low‐potential active sites of sp2 hybridized carbon and carbon vacancies, endowing a low‐potential “vacancy‐adsorption/intercalation” mechanism. The as‐prepared carbon anode exhibits a high capacity of 384.2 mAh g−1 (90 % capacity locates below 1 V vs. K/K+), which contributes to a high energy density of 163 Wh kg−1 of K‐ion full battery. Moreover, abundant vacancies of carbon alleviate volume variation, boosting the cycling stability over 14 000 cycles (8400 h). Our work provides a new synthesis approach for durable carbon anodes of K‐ion full cells with high energy densities.

Nitrogen and Sulfur Codoped Hierarchical Porous Carbon Derived from Lignin for High-Performance Zinc Ion Capacitors

“…It has been reported that this change is associated with the attachment of the C–S bonds to the carbon radicals of tannic acid. Subsequently, these bonds undergo volatilization, leading to the formation of carbon vacancies . In the current investigation, the LNS curve did not exhibit any discernible N peak, whereas the LKNS curve displayed a peak for the C–N bond, thus implying the possibility of nitrogen doping at temperatures exceeding 450 °C.…”

“…The weakening or disappearance of these groups facilitated the opening of the blocked pores, thereby contributing to the generation of plenty of pores during the activation of carbon-based materials. Additionally, the disappearance of peaks for π bonds situated at 2500 and 2392 cm –1 with addition of dopant was ascribed to the replacement of carbon atoms in the aromatic ring by N/S and the subsequent formation of new bonds . This resulted in the destruction of the electronic structure, which further affected the content of the two bonds.…”

“…Subsequently, these bonds undergo volatilization, leading to the formation of carbon vacancies. 48 In the current investigation, the LNS curve did not exhibit any discernible N peak, whereas the LKNS curve displayed a peak for the C− N bond, thus implying the possibility of nitrogen doping at temperatures exceeding 450 °C. Nevertheless, it is reasonable to speculate that the bonding-breaking-volatilization-perforation phenomenon may also exist during the nitrogen doping procedure.…”

“…Additionally, the disappearance of peaks for π bonds situated at 2500 and 2392 cm −1 with addition of dopant was ascribed to the replacement of carbon atoms in the aromatic ring by N/S and the subsequent formation of new bonds. 48 This resulted in the destruction of the electronic structure, which further affected the content of the two bonds. Furthermore, the disappearance of the peak for C−S bonds at 810 cm −1 in LKNS, compared to LNS, was investigated.…”

Direct Microstructure Tailoring of Hard Carbon Electrodes for Fabrication of Dual-Carbon Potassium-Ion Hybrid Supercapacitors

“…The b value was used to describe the electrochemical K + storage behavior, which was dominated by diffusion-controlled (b = 0.5) and capacitive-controlled (b = 1.0) storage mechanisms. 50 The b values at the cathodic peaks of the CWC-700, CWC-900, and CWC-1100 electrodes are 0.89, 0.79, and 0.60, respectively. These results suggest that surface-driven charge storage (capacitive-controlled behavior) is dominant in CWC-700.…”