Work

Effect of K+ incorporation on the interlayer structure and electrochemical performance of Na2V6O16 cathodes for sodium-ion batteries

Year: 2026

Type: article

Abstract: The development of high-performance cathode materials remains a critical challenge for advancing sodium-ion battery (SIB) technology. Na 2 V 6 O 16 , a layered vanadate, is promising due to its large interlayer spacing but suffers from sluggish reaction kinetics and structural degradation during deep cycling. Herein, we propose a novel potassium-ion (K + ) doping strategy to simultaneously tailor the crystal structure and electronic properties of Na 2 V 6 O 16 . A series of K + -doped K x Na 2 V 6-x O 16 (x=0, 0.8, 1.0, 1.2) nanowires were synthesized via a facile one-pot hydrothermal method. Comprehensive characterization reveals that the incorporation of larger K + ions (1.38 Å) significantly expands the interlayer spacing and induces a partial reduction of V 5+ to V 4+ to maintain charge balance, thereby enhancing both Na + diffusion and electronic conductivity.Electrochemical tests demonstrate that the optimal KNa 2 V 5 O 16 cathode exhibits a reversible capacity of approximately 180 mAhg -1 at 0.1 C, outstanding rate capability (120 mAhg -1 at 5 C, corresponding to a capacity retention of 60% relative to 0.1 C), and exceptional long-term cycling stability with continuous capacity growth from approximately 180 to 210mAhg -1 during 700 cycles at 2 C (an increase of 18%).The continuous capacity growth may possibly be attributed to multiple synergistic factors, including progressive electrode wetting, SEI film evolution, and microstructural reconstruction of the active material, rather than solely to intrinsic activation. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses confirm a substantial reduction in charge-transfer resistance and enhanced interfacial charge-transfer kinetics upon K + doping. This work demonstrates that rational doping with larger alkali metal ions is an effective strategy to unlock the full potential of vanadium-based oxides for SIBs.

Source: International Journal of Electrochemical Science

DOI: 10.1016/j.ijoes.2026.101526

Authors: Jie Fang, Wenchang Shen, Wenjie Wang, Jianwei Xu, Peng Lv, Shibin Liu

Institution: Jiamusi University

Language: English

Topic: Advancements in Battery Materials

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $1,670