本研究以固態反應法合成尖晶石結構的MnV₂O₄，作為鋰離子電池之陽極材料，並探討其電化學性能與材料物性之間的關聯性。透過調變電流密度及施加不同方向（與電流平行與垂直）之外加磁場，進行循環的充放電測試與電化學阻抗譜量測，以深入分析材料老化效應與其電池性能之關係。
經過實驗發現，在多圈數循環充放電後，SEI膜與鋰離子與介面產生取向極化的電阻會影響到電池的穩定性，電荷轉移的電阻與MnV₂O₄氧化還原相關，電荷轉移電阻值並沒有太大的變化，表示MnV₂O₄結構並沒有太大變化，結構穩定可承受多圈數循環。施加與電流垂直/平行磁場後發現整體電阻小於未施加磁場，顯示施加磁場後電池電化學性能上升，但400圈後整體電阻上升且大於未施加磁場的電阻，顯示施加磁場雖能提升電化學性能，但長時間循環電池老化效應較明顯，且擴散速率會受磁場的影響，平行磁場下離子行進路徑最長，擴散速率變小，而垂直磁場與未施加磁場的擴散速率表現相近，但垂直磁場的離子行走路徑會受霍爾效應影響，行走路徑比未施加磁場的路徑短，因此擴散速率比未施加磁場的大。
本研究顯示了以MnV₂O₄作為鋰離子電池陽極材料，在低電流密度操作條件下表現較佳，且施加磁場可有效提升其電池性能，這反應出磁場具有對電化學反應之潛在調控能力。

Spinel-structured MnV₂O₄ was synthesized via a solid-state reaction and systematically evaluated as an anode material for lithium-ion batteries. Electrochemical performance was examined under varied current densities and in the presence of both parallel and perpendicular external magnetic fields.
The results indicate that MnV₂O₄ retains its structural integrity during extended cycling, showing only minimal variation in charge-transfer resistance. The application of a magnetic field was found to reduce overall resistance and enhance performance, although prolonged cycling under such conditions revealed accelerated aging effects. Notably, diffusion behavior exhibited strong orientation dependence: when the magnetic field was applied parallel to the current, ion migration paths were elongated, leading to reduced diffusion rates, whereas perpendicular fields, influenced by the Hall effect, shortened ion trajectories and promoted enhanced diffusion.
These findings underscore the structural stability and performance potential of MnV₂O₄ as an anode material, while also highlighting the role of magnetic-field modulation as a promising strategy for tuning electrochemical processes in lithium-ion batteries.

[1] A. Yoshino, "The birth of the lithium-ion battery," Angew. Chem. Int. Ed. 51, 5798-5800
(2012).
[2] Kamat, P. V. (2019). Lithium-ion batteries and beyond: Celebrating the 2019 Nobel Prize in chemistry–a virtual issue. ACS Energy Letters, 4(11), 2757-2759.
[3] M. V. Reddy, G. V. Subba Rao, and B. V. R. Chowdari, "Metal oxides and oxysalts as anode
materials for Li-ion batteries," Chem. Rev. 113, 5364-5457 (2013).
[4] M. Keppeler and M. Srinivasan, "Interfacial phenomena/capacities beyond conversion
reaction occurring in nano-sized transition-metal-oxide-based negative electrodes in
lithium-ion batteries: A review," ChemElectroChem 4, 2727-2754 (2017).
[5] J.-S. Lu, I. V. B. Maggay, and W.-R. Liu, "CoV₂O₄: a novel anode material for lithium-ion
batteries with excellent electrochemical performance," Chem. Commun. 54, 3094-3097
(2018).
[6] L. Hu, H. Zhong, X. Zheng, Y. Huang, P. Zhang, and Q. Chen, "CoMn₂O₄ spinel hierarchical
microspheres assembled with porous nanosheets as stable anodes for lithium-ion batteries,"
Sci. Rep. 2, 986 (2012).
[7] J. M. Won, S. H. Choi, Y. J. Hong, Y. N. Ko, and Y. C. Kang, "Electrochemical properties
of yolk-shell structured ZnFe₂O₄ powders prepared by a simple spray-drying process as
anode material for lithium-ion batteries," Sci. Rep. 4, 5857 (2014).
[8] X. Jiang, J. Liu, P. Zhang, W. Wang, J. Zhou, F. Ye, L. Wang, B. Zhu, and L. Chen, "Spinel-
structured MnV₂O₄@nitrogen-doped carbon microspheres for sodium-ion batteries with
ultra-long cycle stability," J. Alloys Compd. 959, 170594 (2023).
[9] S. Li, Q. Mi, L. Wang, Y. Li, L. Chen, and J. Wang, "Unlocking the potential of spinel
MnV₂O₄ for highly durable aqueous zinc-ion batteries," J. Power Sources 612, 234821
(2024).
[10] W. Leng, L. Cui, Y. Liu, and Y. Gong, "MOF-derived MnV₂O₄/C microparticles with
graphene coating anchored on graphite sheets: oxygen defect engaged high-performance
aqueous zinc-ion battery," Adv. Mater. Interfaces 9, 2101705 (2022).
[11] S. Wei, S. Chen, X. Su, Z. Qi, C. Wang, B. Ganguli, P. Zhang, K. Zhu, Y. Cao, Q. He, D.
Cao, X. Guo, W. Wen, X. Wu, P. M. Ajayan, and L. Song, "Manganese buffer induced
high-performance disordered MnVO cathodes in zinc batteries," Energy Environ. Sci. 14,
3954-3964 (2021).
[12] X. Wang, Z. Jia, J. Zhang, X. Ou, B. Zhang, J. Feng, F. Hou, and J. Liang, "Nanophase
MnV₂O₄ particles as anode materials for lithium-ion batteries," J. Alloys Compd. 852,
156999 (2021).
[13] N. Wen, S. Chen, Q. Lu, Q. Fan, Q. Kuang, Y. Dong, and Y. Zhao, "Cubic MnV₂O₄
fabricated through a facile sol–gel process as an anode material for lithium-ion batteries:
morphology and performance evolution," Dalton Trans. 51, 4644-4652 (2022).
[14] F. Jing, J. Pei, Y. Zhou, Z. Qin, B. Cong, K. Hua, and G. Chen, "Hierarchical MnV₂O₄
double-layer hollow sandwich nanosheets confined by N-doped carbon layer as anode for
high-performance lithium-ion batteries," J. Colloid Interface Sci. 607, 538-545 (2022).
[15] N. Kasai and M. Kakudo, X-Ray Diffraction by Macromolecules (Springer, Berlin, 2005).
[16] N. W. Ashcroft and N. D. Mermin, Solid State Physics (Saunders College, Philadelphia,
1976).
[17] H. Stanjek and W. Häusler, "Basics of X-ray diffraction," Hyperfine Interact. 154, 107-
119 (2004).
[18] P. Roy and S. K. Srivastava, "Nanostructured anode materials for lithium-ion batteries," J.
Mater. Chem. A 3, 2454-2484 (2015).
[19] C. Heubner, S. Maletti, O. Lohrberg, T. Lein, T. Liebmann, A. Nickol, M. Schneider, and
A. Michaelis, "Electrochemical characterization of battery materials in 2-electrode half-cell
configuration: A balancing act between simplicity and pitfalls," Batteries & Supercaps 4,
1310-1322 (2021).
[20] Xie, J., Yang, P., Wang, Y., Qi, T., Lei, Y., & Li, C. M. (2018). Puzzles and confusions in supercapacitor and battery: Theory and solutions. Journal of Power Sources, 401, 213-223.
[21]Huang, X., Wang, Z., Knibbe, R., Luo, B., Ahad, S. A., Sun, D., & Wang, L. (2019). Cyclic voltammetry in lithium–sulfur batteries—challenges and opportunities. Energy Technology, 7(8), 1801001.
[22]Yamada, H., Yoshii, K., Asahi, M., Chiku, M., & Kitazumi, Y. (2022). Cyclic voltammetry part 1: fundamentals. Electrochemistry, 90(10), 102005-102005.
[23] Verma, P., Maire, P., & Novák, P. (2010). A review of the features and analyses of the solid electrolyte interphase in Li-ion batteries. Electrochimica Acta, 55(22), 6332-6341.
[24] E. Peled, "The electrochemical behavior of alkali and alkaline-earth metals in non-aqueous
battery systems—the solid electrolyte interphase model," J. Electrochem. Soc. 126, 2047-
2051 (1979).
[25] A. C. Lazanas and M. I. Prodromidis, "Electrochemical impedance spectroscopy—A
tutorial," ACS Meas. Sci. Au 3, 162-193 (2023).
[26] W. Choi, H.-C. Shin, J. M. Kim, J.-Y. Choi, and W.-S. Yoon, "Modeling and applications
of electrochemical impedance spectroscopy (EIS) for lithium-ion batteries," J. Electrochem.
Sci. Technol. 11, 1-13 (2020).
[27] Q.-C. Zhuang, Y. Li, H. Tang, and C. Zhang, "Diagnosis of electrochemical impedance
spectroscopy in lithium-ion batteries," Lithium Ion Batteries—New Developments, Vol. 8,
189-227 (2012).
[28] Q.-C. Zhuang, Y. Li, H. Tang, and C. Zhang, "An electrochemical impedance
spectroscopic study of the electronic and ionic transport properties of spinel LiMn₂O₄," J.
Phys. Chem. C 114, 8614-8621 (2010).
[29] Zeng, D., Qi, K., & Qiu, Y. (2021, November). Constructing hierarchically porous MnO/C composite to induce diffusion kinetics for high-performance lithium-ion batteries. In Journal of Physics: Conference Series (Vol. 2076, No. 1, p. 012070). IOP Publishing.
[30] Zhang, X., Zhang, Y., Hu, Y., Lin, Y., Li, X., Li, S., & Yang, T. (2022). Two-Step Rapid Synthesis of MnO@C Nanoparticle as a High-Performance Anode for Lithium-Ion Batteries. JOM, 74(5), 1849-1858.
[31] Lai, S. Y., Cavallo, C., Abdelhamid, M. E., Lou, F., & Koposov, A. Y. (2021). Advanced and emerging negative electrodes for Li-ion capacitors: pragmatism vs. performance. Energies, 14(11), 3010.
[32] Yang, C., Ji, X., Fan, X., Gao, T., Suo, L., Wang, F., ... & Wang, C. (2017). Flexible aqueous Li‐ion battery with high energy and power densities. Advanced materials, 29(44), 1701972.