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Updated: Jun 10, 2025
Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques
Published on: November 11, 2013
Electrolyte-Salts Regulated Hydrogen-Bonding Configuration and Interphase Formation Achieving Highly Stable Anode for
Meijing Wang1, Jiaojiao Zhao1, Yangyang Zhang1
1College of Chemistry & Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin, 150040, China.
Abstract:
Hydrogen evolution reactions that cause the alkalization of aqueous electrolytes generally frustrate the structural stability and cycling performance of NaTi2(PO4)3/C anode material for rechargeable aqueous sodium-ion batteries (ASIBs). Herein, a novel highly concentrated electrolyte with a large hydrogen-evolution overpotential and hydroxide-capture ability is rationally established by incorporating a bifunctional Mg(Ac)2 additive into a concentrated NaAc aqueous solution. The highly concentrated electrolyte salts (4m NaAc+3m Mg(Ac)2) favor regulation on hydrogen-bonding configurations and kinetically shift the hydrogen evolution potential to a lower value of -1.37 V (vs Ag/AgCl). The Mg(Ac)2 additive plays particular roles in spontaneously capturing hydroxide ions generated during hydrogen evolution reactions on anode surfaces and simultaneously forming a protective Mg(OH)2-like interphase. As a result, the unique electrolyte significantly improves the structural stability and cycling performance of NaTi2(PO4)3/C anode (94.8% capacity retention after 100 cycles at 100 mA·g-1). The effect of salt concentration on hydrogen bonding configurations of aqueous electrolytes is investigated with Raman spectroscopy and FTIR spectroscopy. The interphase is identified by coupling EDS mapping, X-ray photoelectron spectroscopy, and X-ray diffraction. This work provides a new strategy for improving the cycling stability of aqueous sodium-ion batteries.
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