Building Better Performing Rechargeable Batteries

Jiajun Wang, Karen Chen and Jun Wang

Jiajun Wang, Karen Chen and Jun Wang prepare a sample for study at NSLS beamline X8C.

Brookhaven scientists have made the first 3D observations of how the structure of a lithium-ion battery anode evolves at the nanoscale in a real battery cell as it discharges and recharges. The details of this research could point to new ways to engineer battery materials to increase the capacity and lifetime of rechargeable batteries.

"This work offers a direct way to look inside the electrochemical reaction of batteries at the nanoscale to better understand the mechanism of structural degradation that occurs during a battery's charge/discharge cycles," said Brookhaven physicist Jun Wang, who led the research. "These findings can be used to guide the engineering and processing of advanced electrode materials and improve theoretical simulations with accurate 3D parameters."

Chemical reactions in which lithium ions move from a negatively charged electrode to a positive one are what carry electric current from a lithium-ion battery to power devices such as laptops and cell phones. When an external current is applied - say, by plugging the device into an 
outlet - the reaction runs in reverse to recharge the battery. 

Scientists have long known that repeated charging/discharging (lithiation and delithiation) introduces microstructural changes in the electrode material, particularly in some high-capacity silicon and tin-based anode materials. These microstructural changes reduce the battery's capacity - the energy the battery can store - and its cycle life - how many times the battery can be recharged over its lifetime. Understanding in detail how and when in the process the damage occurs could point to ways to avoid or minimize it. 

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2014-4827  INT/EXT  |  Media & Communications Office

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