Tunable Reaction Potentials in Open Framework Nanoparticle Battery Electrodes for Grid-Scale Energy Storage

Abstract

The electrical energy grid has a growing need for energy storage to address short-term transients, frequency regulation, and load leveling. Though electrochemical energy storage devices such as batteries offer an attractive solution, current commercial battery technology cannot provide adequate power, and cycle life, and energy efficiency at a sufficiently low cost. Copper hexacyanoferrate and nickel hexacyanoferrate, two open framework materials with the Prussian Blue structure, were recently shown to offer ultralong cycle life and high-rate performance when operated as battery electrodes in safe, inexpensive aqueous sodium ion and potassium ion electrolytes. In this report, we demonstrate that the reaction potential of copper-nickel alloy hexacyanoferrate nanoparticles may be tuned by controlling the ratio of copper to nickel in these materials. X-ray diffraction, TEM energy dispersive X-ray spectroscopy, and galvanostatic electrochemical cycling of copper-nickel hexacyanoferrate reveal that copper and nickel form a fully miscible solution at particular sites in the framework without perturbing the structure. This allows copper-nickel hexacyanoferrate to reversibly intercalate sodium and potassium ions for over 2000 cycles with capacity retentions of 100% and 91%, respectively. The ability to precisely tune the reaction potential of copper-nickel hexacyanoferrate without sacrificing cycle life will allow the development of full cells that utilize the entire electrochemical stability window of aqueous sodium and potassium ion electrolytes.

Electrode Materials for Sodium-Ion Batteries: Considerations on Crystal Structures and Sodium Storage Mechanisms

“…Many reported PBAs exhibit low alkaline content [92,[94][95][96][97][98]. Furthermore, although alkaline-rich PBAs were synthesized [87,[99][100][101], the electrochemical process of these PBAs is limited by one-electron reaction due to the highest oxidation state of transition metal in the large interstitial sites, such as Na 1.4 4− oxidation could be effectively suppressed and the Na content can reach as high as 1.63 per formula unit in the presence of ascorbic acid (VC) or under a nitrogen environment during the synthesis process [107].…”

A Safer Sodium‐Ion Battery Based on Nonflammable Organic Phosphate Electrolyte

“…Similar to their Li counterparts,1 though sodium‐based system has similar electrochemical reaction characteristics compared to lithium‐based one, the larger ionic radius for sodium ion cause sluggish kinetics and volume change during Na storage, leading to lower capacity, poor cycling and rate properties of the Na storage materials. Recently, major efforts have been devoted to promote the electrochemical performance of Na storage materials, for example, Na x MO 2 ,2, 3, 4, 5, 6, 7, 8, 9, 10 polyanionic framework compounds,11, 12, 13, 14, 15, 16, 17, 18, 19 hexacyanoferrate,20, 21, 22, 23, 24, 25, 26, 27 for the cathode materials, and hard carbons,28, 29, 30, 31, 32, 33 alloys,34, 35, 36, 37, 38, 39, 40, 41 oxides,42, 43 sulfides37, 44, 45, 46 for the anode materials.…”

Full open-framework batteries for stationary energy storage

“…We recently demonstrated promising results with a new family of battery electrode materials based on the common, inexpensive Prussian Blue pigment [8][9][10][11] . Electrodeposited thin films of these materials have received substantial study in the past for their electrochromic properties, beginning with the pioneering work of Neff 12,13 .…”

“…The result is an extremely stable electrode: over 40,000 deep discharge cycles were demonstrated in the case of the Cu II -N C-Fe III/II cathode 10 . We later showed that related cathode materials including nickel hexacyanoferrate (Ni II -N C-Fe III/II ) 11 also have a very long cycle life when operated in a wide variety of aqueous alkali-ion electrolytes 8 , and that their reaction potentials can be controlled by altering their composition 9 .…”