Sodium-ion batteries face greater safety hazards due to sodium clusters, study finds

A brand new research led by the Qingdao Institute of Bioenergy and Bioprocess Expertise of the Chinese language Academy of Sciences has recognized important security dangers in sodium-ion batteries (SIBs), particularly in comparison with lithium-ion batteries (LIBs).

Printed in Vitality & Environmental Sciencethe study reveals that SIBs are extra vulnerable to thermal runaway than beforehand assumed, difficult their perceived security regardless of price and useful resource benefits.

Over the previous decade, SIBs have achieved vitality densities of as much as 160 Wh/kg and cycle lives exceeding 4,000 charge-discharge cycles. Regardless of these developments, security stays a vital concern. This research highlights the function of sodium clusters in exhausting carbon (HC) anodes, which might set off early thermal runaway. These clusters exhibit digital exercise surpassing even metallic sodium, creating localized “electronic storms” throughout the battery.

Prof. Cui Guanglei, a co-corresponding writer of the research, defined, “When the battery reaches critical charge levels, sodium clusters lower the self-heating onset temperature to as low as 92°C, triggering thermal runaway much earlier than in LIBs.” These clusters act as catalysts, accelerating electrolyte decomposition and intensifying thermal runaway.

Utilizing solid-state nuclear magnetic resonance (ssNMR) spectroscopy, the researchers investigated sodium clusters on the quantum scale. They discovered that these clusters exhibit important metallicity, with extra conduction electrons on the Fermi vitality degree than bulk metallic sodium, making them extremely reactive and accelerating thermal runaway.

In contrast to LIBs, the place exothermic reactions are unbiased of the state of cost (SOC), SIBs exhibit a powerful dependence between response onset and SOC. Sodium clusters kind at elevated SOCs, decreasing the onset temperature for self-heating properly earlier than the SEI decomposition usually seen in LIBs. The research means that even throughout regular operation, SIBs could face security dangers similar to these related to sodium plating in overcharged batteries.

These findings bridge a vital data hole in understanding the connection between cell safety and sodium storage microenvironments. The analysis crew means that changing liquid electrolytes with solid-state supplies might considerably scale back thermal runaway dangers, providing a safer various for future vitality storage.