Boosting Aqueous Zn‐Ion Battery Performances with Mg‐Vanadate Positive and Cu‐Metal Organic Framework Negative Electrodes in Inorganic Gel Electrolyte

Aqueous Zn‐ion batteries (AZIBs) are attractive, cost‐effective, safe, and environmentally friendly energy storage solutions for stationary solar energy applications; offering a balanced combination of energy, power, and durability. A key challenge for AZIBs is the slow diffusion kinetics of divalent Zn²⁺ ions within the host lattices. To address this, Mg_xV₂O₅ (MgVO) as the positive and Cu‐BTC metal organic framework (Cu‐BTC MOF) (BTC: benzene‐1,3,5‐tricarboxylic acid) as the negative electrodes are designed, both of which support Zn²⁺ ion intercalation/deintercalation. The incorporation of Mg²⁺ into the V₂O₅ layer improves Zn²⁺ ion diffusion and enhances electrode stability, mitigating common issues such as layer‐collapse. The Cu‐BTC framework, with its open structure, facilitates efficient Zn²⁺ intercalation, significantly improving energy and power characteristics. A MgVO//Cu‐BTC full cell, utilizing a ZnSO₄‐silica gel electrolyte, delivers a high energy‐density of 305 Wh kg⁻¹ (@ 394 W kg⁻¹) and a notable power‐density of 1773 W kg⁻¹ (@ 87 Wh kg⁻¹), with stable cycling performance (≈86% capacity retention) over 200 cycles at 600 mAh g⁻¹. Additionally, the successful demonstration of a 4.5 V AZIB prototype powering a 3 V light‐emitting‐diode setup under solar charging shows its practical potential. With superior performance, safety, and cost‐effectiveness, this AZIB offers great promise for large‐scale solar energy storage.