Ultrafast Potassium Storage in F-Induced Ultra-High Edge-Defective Carbon Nanosheets

Abstract

Carbonaceous materials have been considered as promising anodes for potassium-ion batteries (PIBs) because of their high electronic conductivity, eco-friendliness, and structural stability. However, the small interlayer spacing and serious volume expansion caused by the repeated insertion/extraction of large K-ions restrict their potassium-ion storage performance. Herein, F and N codoped carbon nanosheets (FNCS) with rich-edge defects are designed to resolve these problems. The F doping is in favor of the formation of more edge defects in the carbon layer, offering strong K + adsorption capability and promoting the K + storage. The ultrathin carbon nanosheets can provide a large contact area for the electrochemical reactions and shorten the transportation pathways for both Kions and electrons. Consequently, the FNCS anode shows a high reversible capacity (610 mAh g −1 at 0.1 A g −1 ) and ultrastable cyclability over 4000 cycles at 5 A g −1 . Moreover, K-ion full cells (FNCS|K 2 FeFe(CN) 6 ) display excellent cycling stability (128 mAh g −1 at 1 A g −1 after 500 cycles) and rate capability (93 mAh g −1 at 20 A g −1 ). This design strategy can be extended to design other electrode materials for high-performance energy storage, such as magnesium-ion batteries, supercapacitors, and electrocatalysis.

Homologous MXene‐Derived Electrodes for Potassium‐Ion Full Batteries

“…During the discharge process, the I D /I G value increases from 1.6 to 2.45 (Figure 4d), which demonstrates an increased amorphization degree with the intercalation of K + . [1] The value of I D /I G decreases gradually in the charge processes and nearly recovers to the initial value when charged back to 3 V. This indicates good reversibility of the NMD-MOF electrode during the K + intercalation and de-intercalation.…”

“…Potassium has advantages over lithium in elemental abundance (≈850 times more than lithium), ionic diffusion coefficient (≈3 times larger than Li + ), and Stokes' radius (3.6 Å vs 4.8 Å). [1][2][3] Encouragingly, K/K + has a comparable potential to that of Li/ Li + (−2.94 V to −3.05 V, vs E 0 ). [4] This renders potassium-ion battery (PIB) with high cell voltage and energy density, which thus is a promising alternative to the lithium-ion battery (LIB).…”

Boosting K+ Capacitive Storage in Dual‐Doped Carbon Crumples with B–N Moiety via a General Protic‐Salt Synthetic Strategy

“…[21] Moreover, conventional synthetic routes for preparing dual-doped carbons either require hard templates with tedious etching procedures or lack generic doping strategies for scalable productions. [22,23] With the consideration of the challenges listed above, we report herein the generic design of heteroatom dual-doped carbon crumples via a protic-salt synthetic route for the employment of the anodes in PIBs. [24,25] Benefiting from the versatility of protic base and acid materials, sulfur-, phosphorus-and boron-nitrogen co-doped carbon (SNC, PNC, and BNC) architectures can be readily obtained by varying the contents and types of precursors.…”

Ultra-Low-Dose Pre-Metallation Strategy Served for Commercial Metal-Ion Capacitors

“…It was found that the reflection of electrode located at 34.4° indexed to lattice plane of (4 0 0) and two characteristic peaks of C=O stretching vibration of Na 2 C 2 O 4 substance were absolutely disappeared after charging to 4.3 V (Fig. 6 a–b), clearly revealing the first charging process enables sodium release from sodium oxalate [ 41 ]. Moreover, optical photograph (Fig.…”