Edge Graphitized Oxygen‐Rich Carbon Based on Stainless Steel‐Assisted High‐energy Ball Milling for High‐Capacity and Ultrafast Sodium Storage

Abstract

Oxygen doping is an effective strategy for constructing high‐performance carbon anodes in Na ion batteries; however, current oxygen‐doped carbons always exhibit low doping levels and high‐defect surfaces, resulting in limited capacity improvement and low initial Coulombic efficiency (ICE). Herein, a stainless steel‐assisted high‐energy ball milling is exploited to achieve high‐level oxygen doping (19.33%) in the carbon framework. The doped oxygen atoms exist dominantly in the form of carbon‐oxygen double bonds, supplying sufficient Na storage sites through an addition reaction. More importantly, it is unexpected that the random carbon layers on the surface are reconstructed into a quasi‐ordered arrangement by robust mechanical force, which is low‐defect and favorable for suppressing the formation of thick solid electrolyte interfaces. As such, the obtained carbon presents a large reversible capacity of 363 mAh g−1 with a high ICE up to 83.1%. In addition, owing to the surface‐dominated capacity contribution, an ultrafast Na storage is achieved that the capacity remains 139 mAh g−1 under a large current density of 100 A g−1. Such good Na storage performance, especially outstanding rate capability, has rarely been achieved before.

Molecular Engineering Enabling High Initial Coulombic Efficiency and Rubost Solid Electrolyte Interphase for Hard Carbon in Sodium‐Ion Batteries

“…[16] The refined spectra of Na 1s for HC and DP‐HC are shown in Figure 3l. A single peak situated at 1072.5 eV is the characteristic peak of Na 2 O [8a,17] . Therefore, the SEI components of DP‐HC are mainly contributed by Na 2 CO 3 , NaF and Na 2 O.…”

High-Energy Ball Milling Promoted Sulfur Immobilization for Constructing High-Performance Na-Storage Carbon Anodes

“…CFG and CFG-S exhibit low ICEs of 65.5 and 62.3%, respectively, close to those of most other pristine or heteroatom-doped carbon anodes with a heating treatment temperature of <1000 °C. However, CFG-S-M exhibits a very high ICE of 91.2%, which is rarely achieved in the S-doped carbon anode and comparable to those of most other carbon anodes that exhibit outstanding ICE values because they underwent complicated surface modification or presodiation technologies. ,− …”

“…Heteroatom doping is a useful strategy to modify carbon anodes and solve their current shortcomings. As one of the commonly used doping atoms (e.g., O, N, S, and P), S doping considerably promotes sodium storage. − On the one hand, S can form Na 2 S x compounds via redox reactions with Na + , contributing numerous sodium storage sites along with high capacity. On the other hand, the large atomic radius of S increases the layer spacing in carbon materials after S doping, promoting the intercalation of Na + into the carbon structure.…”

Design guidelines for a high-performance hard carbon anode in sodium ion batteries

“…4f). Several nanocarbons based on surface and/or bulk chemisorption mechanisms show reversible capacities of 120–380 mA h g −1 and high voltage of 1.0–1.6 V. 53–71 In the case of hard carbons, higher reversible capacities of 220–480 mA h g −1 and lower average voltage ranges of 0.2–0.6 V were achieved. 15–17,19,20,22–34,47–52 The PHC-series samples in this study also showed reversible capacities and voltages similar to those of previously reported hard carbon materials.…”