by Michael D’Agati

Most aspects of electrical design and electrical engineering, such as circuits, wouldn’t be possible without batteries. Good batteries have a large capacity, high power density (quick charge/discharge cycles), and low cost energy storage. A few different types of rechargeable batteries have been developed, but at low temperatures, like -15°C, they charge slowly. This results in a severe voltage drop that can trigger problems elsewhere in electrical applications, and cause safety hazards.

A new study focused on improving the capabilities of energy storage devices, such as batteries, has recently emerged. At the Harbin Institute of Technology in China, Dr. Tiefeng Liu, along with his team of researchers from Griffith University in Australia and Berkeley National Laboratory in California, developed a sodium ion battery that can deliver a discharge capacity of 115.3 and 85.5mAh g-1 at +55°C and -30°C respectively. The sodium ion batteries have shown to maintain a good discharge capacity at low temperatures (91.3 mAh g-1 at -20°C, which is 85.2% the performance at 10°C), and have great wide-temperature attributes. They created the battery by using Na Super Ionic Conductor (NASICON) crystalline structure electrode materials.  The research group used Na3V2 (PO4)3 (NVP) as a typical NASICON material that gives a stable 3-D framework and high Na+ mobility. Although this material provides the necessary wide temperature range and low activation energy, the material has a drawback of low electric conductivity. Therefore, to increase the conductivity, sucrose was used in a ball milling and calcination procedure at high temperatures (300 degrees and 800 degrees) with NaH2PO4 and V2O5 to create a carbon-coated NVP (NVP@C) nanocomposite.

The advances in sodium ion batteries may allow for better batteries overall, possibly even replacing the gold standard of lithium ion batteries we use today. This project provides one of the first steps in improving energy storage technology, which will allow more advances in other technological areas.

References:  

1. T. Liu et al., All-climate sodium ion batteries based on the NASICON electrode materials. Nano Energy (2016). doi: 10.1016/j.nanoen.2016.09.024.
2. Image retrieved from: https://pixabay.com/p-41056/?no_redirect