Water-mediated cation intercalation of open-framework indium hexacyanoferrate with high voltage and fast kinetics.

Liang Chen,Hezhu Shao,Zhaoping Liu,Guoqiang Liu,Xufeng Zhou,Jun Jiang

doi:10.1038/ncomms11982

Abstract

Rechargeable aqueous metal-ion batteries made from non-flammable and low-cost materials offer promising opportunities in large-scale utility grid applications, yet low voltage and energy output, as well as limited cycle life remain critical drawbacks in their electrochemical operation. Here we develop a series of high-voltage aqueous metal-ion batteries based on ‘M+/N+-dual shuttles' to overcome these drawbacks. They utilize open-framework indium hexacyanoferrates as cathode materials, and TiP2O7 and NaTi2(PO4)3 as anode materials, respectively. All of them possess strong rate capability as ultra-capacitors. Through multiple characterization techniques combined with ab initio calculations, water-mediated cation intercalation of indium hexacyanoferrate is unveiled. Water is supposed to be co-inserted with Li+ or Na+, which evidently raises the intercalation voltage and reduces diffusion kinetics. As for K+, water is not involved in the intercalation because of the channel space limitation.

Highlights

Rechargeable aqueous metal-ion batteries made from non-flammable and low-cost materials offer promising opportunities in large-scale utility grid applications, yet low voltage and energy output, as well as limited cycle life remain critical drawbacks in their electrochemical operation
As sodium and potassium are more abundant than lithium, rechargeable aqueous metal-ion batteries (RAMB) with Na þ and K þ shuttles are considered as more competitive power sources for large-scale energy storage
It is found that the metal hexacyanoferrate (MeHCF) with open-framework structure allowing for coinsertion/extraction of alkali cations can act as a promising cathode candidate for aqueous mixed-ion batteries (AMIB)

Summary

Introduction

Rechargeable aqueous metal-ion batteries made from non-flammable and low-cost materials offer promising opportunities in large-scale utility grid applications, yet low voltage and energy output, as well as limited cycle life remain critical drawbacks in their electrochemical operation. We develop a series of high-voltage aqueous metal-ion batteries based on ‘M þ /N þ -dual shuttles’ to overcome these drawbacks. They utilize open-framework indium hexacyanoferrates as cathode materials, and TiP2O7 and NaTi2(PO4)[3] as anode materials, respectively. The roles of orientation, graphene and guest species on its rate capability are extensively studied By combining it with carbon-coated TiP2O7 and NaTi2(PO4)[3] as anode materials, a series of AMIB with high-voltage output Z1.2 V are demonstrated. Water-mediated cation intercalation in InHCF is revealed, using multiple characterization techniques coupled with density functional theory (DFT) calculations

Methods

Results

Conclusion