Smart Mn3O4 cathodes derived from Mn(BTC=1,3,5-benzenetricarboxylic acid) for zinc-ion batteries: light-modulated kinetics and charge storage mechanisms

초록

We report a photoresponsive Zn-ion battery (ZIB) using an ultrathin Mn3O4 cathode derived from Mn(BTC = 1,3,5-benzenetricarboxylic acid) metal-organic framework (MOF) via an additive-free alternating current-electrophoretic deposition method. This approach enables fabrication of an interface-sensitive electrode platform without binders or conductive agents, allowing direct probing of intrinsic photoelectrochemical properties. Upon blue light (450 nm) illumination, the Mn3O4 cathode exhibited a dramatic increase in specific capacity-rising from similar to 1200 to over 2400 mAh g(-1) along with enhanced redox kinetics and broadened voltage plateaus. Cyclic voltammetry and kinetic analyses confirmed that photoactivation primarily boosted diffusion-controlled charge storage, particularly at lower scan rates and current densities. Notably, the photoinduced enhancement persisted even after switching off the light, indicating a lasting interfacial modification. These findings demonstrate the promise of MOF-derived, binder-free photoelectrodes in light-responsive energy storage and provide a platform for understanding photon-coupled ion transport mechanisms at the electrode/electrolyte interface.

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