Surfactant-assisted molecular-level tunning of phenol-formaldehyde-based hard carbon microspheres for high-performance sodium-ion batteries

Yuting Liu; Di Liu; Peng Liu; Changhai Liu; Jisheng Zhou

doi:10.1016/j.jcis.2024.04.019

Surfactant-assisted molecular-level tunning of phenol-formaldehyde-based hard carbon microspheres for high-performance sodium-ion batteries

J Colloid Interface Sci. 2024 Jul 15:666:118-130. doi: 10.1016/j.jcis.2024.04.019. Epub 2024 Apr 4.

Authors

Yuting Liu¹, Di Liu¹, Peng Liu¹, Changhai Liu², Jisheng Zhou³

Affiliations

¹ State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
² School of Materials Science and Engineering, CNPC-CZU Innovation Alliance, Changzhou University, Changzhou 213164, China. Electronic address: liuch@cczu.edu.cn.
³ State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China. Electronic address: zhoujs@mail.buct.edu.cn.

PMID: 38588624
DOI: 10.1016/j.jcis.2024.04.019

Abstract

The phenol-formaldehyde (PF) resin is an economical precursor for spherical hard carbon (HC) anodes for sodium-ion batteries (SIBs). However, achieving precise molecular-level control of PF-based HC microspheres, particularly for optimizing ion transport microstructure, is challenging. Here, a sodium linoleate (SL)-assisted strategy is proposed to enable molecular-level engineering of PF-based HC microspheres. PF microspheres are synthesized through the polymerization of 3-aminophenol and formaldehyde, initially forming oxazine rings and then undergoing ring-opening polymerization to create a macromolecular network. SL functions as both a surfactant to control microsphere size and a catalyst to enhance ring-opening polymerization and increase polymerization of PF resin. These modifications lead to reduced microsphere diameter, increased interlayer spacing, enhanced graphitization, and significantly improved electron and ion transfer. The synthesized HC microspheres exhibit a remarkable reversible capacity of 337 mAh/g, maintaining 96.9 mAh/g even at a high current density of 5.0 A/g. Furthermore, the full cell demonstrates a high capacity of 150 mAh/g, an energy density of 125.3 Wh kg^-1, an impressive initial coulombic efficiency (ICE) of 930.3% at 1 A/g, and remarkable long-term stability over 3000 cycles. This study highlights the potential of surfactant-assisted molecular-level engineering in customizing HC microspheres for advanced SIBs.

Keywords: Hard carbon microspheres; Molecular-level control; Phenolic formaldehyde resin; Sodium ion battery.