Effect of Solution Concentration on the Electrochemical Properties of Electrospun Zinc Phosphate Carbon Nanofibers As Anode Materials for Lithium-Ion Batteries
Authors: Sagynbay Yrysgul , Belgibayeva Ayaulym , Bakenov Zhumabay 
Published: December 2024

Zinc (Zn) is notable for its abundance and environmental friendliness, offering various compounds like zinc oxide, sulfide, selenide, phosphides, and phosphates [1]. While zinc oxide and chalcogenides are well-researched for their use in lithium-ion battery anodes, other zinc compounds, including phosphides and phosphates, remain largely unexplored [2]. Despite limited research on zinc phosphate as an anode material, its unique properties have been recognized across different applications [3,4]. Exploring the synergy between phosphide and phosphate presents an exciting opportunity for advancements.

This work investigates carbon composite nanofibers of zinc phosphates synthesized using the facile electrospinning method directly from polyvinylpyrrolidone (PVP)-containing precursors. The impact of the electrospinning solution on the composition and morphology of the prepared materials was studied. Furthermore, the potential of zinc phosphate and its coupled forms as lithium-ion battery anode materials was elucidated.

Electrospinning solutions were prepared by varying concentrations of zinc nitrate, PVP and phosphoric acid to determine the maximum spinnable concentration with the best physical and electrochemical properties of final samples and electrospun at specified electrospinning parameters. Obtained fibers were dried, pre-oxidized, annealed for 1 h at 750°C in N2 + H2 (4%), and denoted as ZnPO/C samples.

Formation of the desired materials was confirmed by X-Ray diffraction (XRD, Miniflex, Rigaku) and scanning electron microscopy (SEM, Crossbeam500, Zeiss).

The fibrous morphology of the ZnPO/C nanofibers confirmed from SEM images in Figure (a).It also shows homogeneity in fiber shape and size across all concentrations. XRD patterns of ZnPO/C samples of varying concentrations in Figure (b) have shown formation of Zn2P2O7 with some ⍺-Zn3(PO4)2 impurities.The intensities showed an increase corresponding to the concentration of the samples, along with some degree of peak broadening. It might be due to the amorphous carbon regions present in higher concentrations.

Further details of the impact of the concentration on physical and electrochemical properties of the prepared materials will be presented at the conference.

Acknowledgements

This research was funded by the projects AP19675260 “Development of nanofibrous electrode materials for next-generation lithium-ion batteries” and AP13068219 “Development of multifunctional free-standing carbon composite nanofiber mats” from the Ministry of Education and Science of the Republic of Kazakhstan.

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[2] W. Li, L. Gan, K. Guo, L. Ke, Y. Wei, H. Li, G.Shen, T. Zhai, Nanoscale 8 (2016) 8666-8672

[3]Y. Guo, Y. Liu, Y. Li, S. Hou, T. Liu, L. Zhao, Self-assembly of ZnO nanoparticles attached to 3D pleated Zn3(PO4)2/C from cola for enhanced lithium storage, Appl Surf Sci 508 (2020) 145288.

[4]Y. Li, Z.T. Wang, G. Liu, J. Wang, J. Wang, Boosting the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 cathode materials with Zn3(PO4)2 surface coating, Advanced Powder Technology 32 (2021) 4651–4657.

Figure 1