Achieving All‐Plateau and High‐Capacity Sodium Insertion in Topological Graphitized Carbon

Abstract

Hard carbon anodes with all‐plateau capacities below 0.1 V are prerequisites to achieve high energy density sodium ion storages, which are holding promises for the future sustainable energy technologies. However, challenges in removing defects and improving the insertion of sodium ions heading off the development of hard carbon to achieve this goal. Herein, we reported a highly cross‐linked topological graphitized carbon using biomass corn cobs through a two‐step rapid thermal annealing strategy. The topological graphitized carbon constructed with long‐range graphene nanoribbons and cavities/tunnels provides a multi‐directional insertions of sodium ions whilst eliminating defects to absorb sodium ions at high voltage region. Evidences from advanced technique including in‐situ XRD, in‐situ Raman and in‐situ/ex‐situ TEM indicate that the sodium ions appear Na cluster formation between curved topological graphite layers and in the topological cavity of adjacent graphite band entanglements. The reported topological insertion mechanism enables outstanding battery performance with a single full low‐voltage plateau capacity of 290 mAh g−1, which is almost 97% of the total capacity.This article is protected by copyright. All rights reserved

Bridging Microstructure and Sodium-Ion Storage Mechanism in Hard Carbon for Sodium Ion Batteries

“…As shown in Figures a and S10, the intensity of the (002) peak for PG diminishes in the plateau region but increases during the desodiation process, whereas the peak position hardly undergoes a significant shift throughout the process. It is noteworthy that the weakening for intensity of the (002) peak corresponds to the transformation toward disordered structure, which is caused by the insertion of sodium ions between graphite-like layers. , The position of the (002) peak hardly moves because the original d 002 layer spacing (0.375 nm) is large enough to accommodate sodium ions, thus causing no expansion of the layer spacing, which has been reported in some literature. , A similar phenomenon is observed for PG/GL (Figures b, S11), except that the position of the graphite peak (26.36°) also hardly shifts during the discharge process, which is in agreement with the results of in situ Raman analysis, suggesting no sodium ion insertion in graphite-like domains. In particular, for PGS/GL (Figure c) the (002) peak position shifts to a lower angle in the plateau section, evidencing the expansion of the interlayer spacing for pseudographite domains, while a similar phenomenon is not observed for the graphite-like domains (26.20°), further proving the intercalation only occurs in the pseudographitic regions.…”

“…It is noteworthy that the weakening for intensity of the (002) peak corresponds to the transformation toward disordered structure, which is caused by the insertion of sodium ions between graphite-like layers. 24,46 The position of the (002) peak hardly moves because the original d 002 layer spacing (0.375 nm) is large enough to accommodate sodium ions, thus causing no expansion of the layer spacing, which has been reported in some literature. 34,38 A similar phenomenon is observed for PG/GL (Figures 4b, S11), except that the position of the graphite peak (26.36°) also hardly shifts during the discharge process, which is in agreement with the results of in situ Raman analysis, suggesting no sodium ion insertion in graphite-like domains.…”

Intrinsically Nitrogen-Enriched Biomass-Derived Hard Carbon with Enhanced Performance as a Sodium-Ion Battery Anode

“…It is worth noting that the presence of adequate interlayer spacing and oxygenated and nitrogenated functional groups with the optimized open/closed pores facilitates better Na + -ion insertion/extraction for HC-1200. To quantify the sodium-ion diffusion coefficient ( D Na + ) for the prepared HC-1200 electrode, GITT was used, , and presented in Figure S4. As can be seen from the curves, no significant change in the D Na + value was observed in both sodiation (avg.…”

Reappraisal of hard carbon anodes for practical lithium/sodium-ion batteries from the perspective of full-cell matters

“…At present, assembling a half-cell with metal lithium or sodium foil as the counter electrode to evaluate HC anode performance before constructing a full-cell is common practice. However, in SIBs, the results from half-cell studies may not be reliable due to the differences with those obtained from a full-cell, 19–21 particularly in terms of rate and cycle performance. 21–23 This can be attributed to two factors.…”

“…However, in SIBs, the results from half-cell studies may not be reliable due to the differences with those obtained from a full-cell, 19–21 particularly in terms of rate and cycle performance. 21–23 This can be attributed to two factors. (1) Sodium metal reacts strongly with the electrolyte and generates higher ohmic resistance than lithium, resulting in higher ohmic polarization.…”