Diffusion-dominated charge storage in Mn(BTC) cathodes for aqueous Zn-ion batteries

초록

We utilized alternating current electrophoretic deposition (AC-EPD) to construct binder-free Mn-1,3,5-benzenetricarboxylic acid (Mn-BTC) cathodes for aqueous zinc-ion batteries. This technique offers excellent control over film formation, preserving the delicate structure of the material and making it ideal for investigating electrode-electrolyte interactions. The resulting cathode delivered an unprecedented specific capacity of 430 mAh g-1 at 200 mA g-1 with outstanding cycling stability. Initial charge-discharge cycles showed pronounced voltage fluctuations, indicating dynamic interface evolution likely driven by Mn ion dissolution. Kinetic analysis yielded a b-value close to 0.5, confirming a diffusion-limited charge storage mechanism. This is consistent with bulk redox processes within the Mn-BTC framework, including its potential transformation into secondary phases.

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