Researchers in the US have developed a low cost sodium battery that can take on lithium-ion chemistries for energy density and reliability.
The 60mAh sodium battery developed by the team from Washington State University (WSU) and Pacific Northwest National Laboratory (PNNL) has a specific capacity of 196 mAh/g and keeps more than 80 percent of its charge after 1,000 cycles.
There is a lot of interest in sodlium battery chemistry as it can be made cheaply and potentially without cobalt. Companies such as Faradion in the UK are working on commercial sodium battery systems, while labs around the world are working on new materials and processes for sodium battery designs.
The US research was led by Yuehe Lin, professor in WSU’s School of Mechanical and Materials Engineering, and Xiaolin Li, a senior research scientist at PNNL.
“This work paves the way toward practical sodium-ion batteries, and the fundamental insights we gained about the cathode-electrolyte interaction shed light on how we might develop future cobalt-free or low cobalt cathode materials in sodium-ion batteries as well as in other types of battery chemistries,” said Junhua Song, a WSU PhD graduate who is now at Lawrence Berkeley National Laboratory. “If we can find viable alternatives to both lithium and cobalt, the sodium-ion battery could truly be competitive with lithium-ion batteries. And, that would be a game changer.”
The battery uses a layered cathode with sodium, nickel, manganese and cobalt (O3-NaNi0.68Mn0.22Co0.10O2) and a liquid electrolyte that included extra sodium ions to provide a better interaction with their cathode. Their cathode design and electrolyte system allowed for continued movement of sodium ions, preventing inactive ions building up.
“Our research revealed the essential correlation between cathode structure evolution and surface interaction with the electrolyte,” said Lin. “These are the best results ever reported for a sodium-ion battery with a layered cathode, showing that this is a viable technology that can be comparable to lithium-ion batteries.”
The team are working with other materials to improve battery design as well as designing out the use of cobalt.