Prussian Blue MgLi Hybrid Batteries. Issue 8 (15th April 2016)

• Record Type: Journal Article
• Authors: Sun, Xiaoqi; Duffort, Victor; Nazar, Linda F.
• Is Part Of: Advanced science. Volume 3:Issue 8(2016:Aug.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-04-15
• Subjects: Li ion intercalation -- Mg–Li hybrid battery -- Mg negative electrode -- Prussian blue; Science -- Periodicals; 505
• DOI: 10.1002/advs.201600044
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract : The major advantage of Mg batteries relies on their promise of employing an Mg metal negative electrode, which offers much higher energy density compared to graphitic carbon. However, the strong coulombic interaction of Mg 2+ ions with anions leads to their sluggish diffusion in the solid state, which along with a high desolvation energy, hinders the development of positive electrode materials. To circumvent this limitation, Mg metal negative electrodes can be used in hybrid systems by coupling an Li + insertion cathode through a dual salt electrolyte. Two "high voltage" Prussian blue analogues (average 2.3 V vs Mg/Mg 2+ ; 3.0 V vs Li/Li + ) are investigated as cathode materials and the influence of structural water is shown. Their electrochemical profiles, presenting two voltage plateaus, are explained based on the two unique Fe bonding environments. Structural water has a beneficial impact on the cell voltage. Capacities of 125 mAh g −1 are obtained at a current density of 10 mA g −1 (≈C/10), while stable performance up to 300 cycles is demonstrated at 200 mA g −1 (≈2C). The hybrid cell design is a step toward building a safe and high density energy storage system. Abstract : An MgLi hybrid cell is assembled with Prussian blue analogue (PBA) as the cathode material and Mg as the anode, uses a MgLi dual salt electrolyte. In such a system, facile Li + intercalation takes place into the PBA structure whereas dendrite‐free deposition is observed at the anode, providing an average cell voltage of 2.3 V versus Mg/Mg 2+ .