Regulating Oxygen Configuration in Hierarchically Porous Carbon Nanosheets for High‐Rate and Durable Na⁺ Storage

Abstract

Surface oxygen functionalities (particularly C−O configuration) in carbon materials have negative influence on their electrical conductivity and Na+ storage performance. Herein, we propose a concept from surface chemistry to regulate the oxygen configuration in hierarchically porous carbon nanosheets (HPCNS). It is demonstrated that the C−O/C=O ratio in HPCNS reduces from 1.49 to 0.43 and its graphitization degree increases by increasing the carbonization temperature under a reduction atmosphere. Remarkably, such high graphitization degree and low C−O content of the HPCNS‐800 are favorable for promoting its electron/ion transfer kinetics, thus endowing it with high‐rate (323.6 mAh g−1 at 0.05 A g−1 and 138.5 mAh g−1 at 20.0 A g−1) and durable (96 % capacity retention over 5700 cycles at 10.0 A g−1) Na+ storage performance. This work permits the optimization of heteroatom configurations in carbon for superior Na+ storage.

Ion-catalyzed synthesis of N/O co-doped carbon nanorods with hierarchical pores for high-rate Na-ion storage

“…2b, the NOCNRs possess two characteristic peaks, corresponding to the D band (1364 cm −1 ) and G band (1581 cm −1 ), whereas the disordered degree of carbon can be determined by the intensity ratio of D band to G band ( I D / I G ). 23 The I D / I G ratio of 1.163 indicates a low degree of graphitization and a high concentration of defects in NOCNRs, which is in agreement with the results of HRTEM and XRD. FTIR (Fig.…”

“…Suitable oxygen functional groups on the carbon skeleton can enhance the Na + storage of the product carbon. 23 Moreover, the surface functional groups containing N and O could improve the wettability of the electrode to promote electron/ion transportation.…”