Advanced intermediate temperature sodium–nickel chloride batteries with ultra-high energy density

Abstract

Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium–nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg−1, higher than that of conventional tubular sodium–nickel chloride batteries (280 °C), is obtained for planar sodium–nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium–nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

A Low‐Cost Durable Na‐FeCl2 Battery with Ultrahigh Rate Capability

“…For this to happen, during the discharge process, a small amount of FeCl 2 or/and Na 6 FeCl 8 should dissolve in NaAlCl 4 and produce Fe via liquid‐phase reactions. Interestingly, such particle pulverization and resultant capacity fading has not been observed in Ni cathodes . We thus hypothesize that NiCl 2 has much lower solubility in NaAlCl 4 than FeCl 2 and/or Na 6 FeCl 8 have, which was confirmed by the solubility results determined from ICP‐OES measurements (Table S3, Supporting Information).…”

“…Typical voltage profiles (≈ C /16) of Na‐NiCl 2 and Na‐FeCl 2 cells are compared in Figure c. As expected, the voltage profile of the Na‐NiCl 2 cell (black line) points to a reversible redox reaction between Ni and NiCl 2 , with one single plateau each at ≈2.63 and ≈2.57 V for charging and discharging processes, respectively . For the Na‐FeCl 2 cell (red line), the appearance of two plateaus for the charging process indicates a different reaction mechanism.…”

“…For electrochemical energy storage systems targeted at utility‐scale applications, the key requirements are low cost, scalability, and reliability . To this end, we recently developed a planar, intermediate‐temperature (IT) Na‐NiCl 2 battery that greatly advanced Na‐NiCl 2 batteries by stably delivering 350 Wh kg −1 over 1000 cycles at 190 °C . Moreover, reducing the operating temperature simplifies the cell design and enables use of inexpensive polymers for the cell seals .…”

Understanding the Correlation between Electronic Coupling and Energetic Stability of Molecular Crystal Polymorphs: The Instructive Case of Quinacridone

“…31 This is relevant in the present context for several reasons: -stacking is typically considered to be beneficial for the charge-carrier mobility in organic materials. 28,32,33 Consequently, in the following, we will focus on analyzing the electronic coupling in the -stacking direction, as in this direction the largest coupling for a given material can be achieved, provided that the molecules are suitably arranged.…”

Silica‐free sealing glass for sodium‐beta alumina battery

“…Energy storage systems enable to store unused energy and convert it into electrical energy for various applications such as portable consumer electronics, transportation, stationary energy sources, load leveling of grid energy, and storing renewable energy. Rechargeable sodium‐beta alumina (sodium‐sulfur/ZEBRA) battery is suited for high temperature (250‐350°C) energy storage for stationary applications, electronics in automotive and electric vehicles, military and aerospace industries . In sodium‐beta alumina battery, sulfur/nickel chloride serves as positive electrode and sodium as negative electrode.…”