The discovery enables the design of a high-performance, low-cost battery that, according to its developers, outperforms Department of Energy goals on cost and cycle life for grid-scale energy storage.
The widespread deployment of renewable energy sources such as solar and wind power destabilizes the electric grid because conventional power-generation systems cannot ramp quickly enough to balance the power variations from these intermittent sources. Storing energy in batteries could help to even things out, but the cost of most existing technologies—including lithium-ion batteries—is significant, hindering grid-scale applications.
Emerging storage technologies such as aqueous sodium (Na) systems offer low costs for long-duration storage, but they do not have the charge/discharge rates needed to balance volatile power generation. In particular, it remains a critical challenge to develop a stable negative electrode (anode) for high-rate Na-ion battery systems.
A battery breakthrough
Compared with the relatively mature designs of anodes used in Li-ion batteries, anodes for Na-ion batteries remain an active focus of research and development. Natron Energy (formerly Alveo Energy), a battery-technology company based in Santa Clara, California, developed an unconventional anode design using a blend of elements chemically similar to the paint pigment known as Prussian blue.
Image: Atomic structure of an electrode material, manganese hexacyanomanganate (MnHCMn), that achieved high performance in a sodium-ion battery. The open framework contains large interstices and channels that allow sodium (Na) ions to move in and out with near-zero strain. Manganese (Mn) ions form the corners of the cage: Mn(N) has six nitrogen nearest neighbors and Mn(C) has six carbon nearest neighbors.