High-Voltage and Stable Manganese Hexacyanoferrate/Zinc Batteries Using Gel Electrolytes

Because of the high safety and environmental friendliness,aqueouszinc-ion batteries have gained a lot of attention in recent years.Prussian blue and its analogues are regarded as a promising cathodematerial of zinc-ion batteries. Manganese hexacyanoferrate is appropriateamong them due to its high operating voltage, large capacity, andcheap price. However, the poor cycling stability of manganese hexacyanoferrate,mainly caused by transition metal dissolution, side reaction, andphase transition, greatly restricts its practical application. Inthis work, gelatin is used to limit the content of free water in theelectrolyte, thus reducing the dissolution effect of transition metalmanganese. The introduction of gelatin improves the durability ofthe Zn anode as well. The optimized MnHCF/gel-0.3/Zn battery displaysa high reversible capacity (120 mAh center dot g(-1) at0.1 A center dot g(-1)), an excellent rate performance (42.7mAh center dot g(-1) at 2 A center dot g(-1)),and a good capacity retention (65% at 0.5 A center dot g(-1) after 1000 cycles).