Towards Realizing Wearable Batteries: Dual Ion Prussian Blue Analog/Zinc Battery Architecture with Long Cycle Life and High Energy Efficiency
In this work we demonstrate a high potential aqueous Sodium ion battery with high cycle life, to achieve as much as 500 cycles with over 80% cell capacity retention, which is five times of the maximum reported in literature. (Trócoli and La Mantia 2015)The high potential of Zn and high reversibility of Na+ ion cycling in Copper Hexacyanoferrate lattice is exploited in making a considerable improvement over previous Zn/ Zinc Hexacyanoferrate system. We validate the hypothesis that the slow kinetics of zinc intercalation compared to sodium in Hexacyanoferrates enables preferential intercalation of sodium ions and hence reduce zinc poisoning. We further show the use of Hyper Dendritic Zinc (HD Zn) to improve capacity retention and overall kinetics of the system. Prussian Blue has been used as a fabric dye for over 80 years. The relative safety of the dual ion PBA/HD Zn system that we demonstrate helps us step closer to realizing batteries on fibers woven integrated with wearable electronics.