Article

Replacing “Alkyl” with “Aryl” for inducing accessible channels to closed pores as plateau‐dominated sodium‐ion battery anode

Wenlong ShaoState Key Laboratory of Fine Chemicals Department of Polymer Materials & Engineering Liaoning Province Engineering Research Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaQi CaoState Key Laboratory of Fine Chemicals Department of Polymer Materials & Engineering Liaoning Province Engineering Research Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaSiyang LiuSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaTianpeng ZhangSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaZihui SongSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaCe SongSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaZhihuan WengState Key Laboratory of Fine Chemicals Department of Polymer Materials & Engineering Liaoning Province Engineering Research Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaXigao JianSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. ChinaFangyuan HuSchool of Materials Science and Engineering Key Laboratory of Energy Materials and Devices (Liaoning Province) State Key Laboratory of Fine Chemicals Liaoning Province Engineering Centre of High Performance Resins Dalian University of Technology Dalian P. R. China

2022en

ABI

Abstract

Abstract Hard carbons are promising anodes for sodium‐ion batteries. However, there is still considerable controversy regarding the sodium storage behaviors in hard carbons, which are mainly attributed to the varied precursors, confused pyrolysis mechanism, and different characterization methods. Herein, benefiting from the flexible molecular structure of polymers, a series of hard carbons with carefully tuned microstructures are fabricated by adjusting the ratio of aryl and alkyl groups in the epoxy resins. The results of dynamic mechanical analysis, in‐situ Fourier transform infrared spectra, and synchronous thermal gravimetric‐infrared spectrum‐gas chromatography/mass spectrometry reveal that replacing the alkyl with aryl groups in the resin can enhance the crosslink density, inhibit the degradation and rearrangement process, and further lead to a more disordered microstructure. In addition, it is suggested that accessible channels provided by sufficiently wide interlayer spacing are necessary for closed pore filling. The optimized anode delivers a high capacity of 375 mAh/g in half cell with an initial Coulombic efficiency of 80.61%, and an energy density of 252 Wh/kg is attained in full cell. Finally, a reliable relationship among precursor–pyrolysis mechanism–structure–performance is established, and the sodium storage mechanism of “adsorption–insertion–pore filling” is well proved.

Identifiers

DOI: 10.1002/sus2.68

Citations and references

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