Improved potassium ion storage performance of graphite by atomic layer deposition of aluminum oxide coatings

Summary In the context of large scale and low-cost energy storage, the emerging potassium-ion batteries (PIBs) are one potential energy storage system. Graphite, a commercial anode material widely used in lithium-ion batteries (LIBs), can be directly applied to PIBs through forming the stage I graphite intercalation compound (KC 8 ). However, the dramatic volume expansion during the formation of KC 8 can result in poor cycling performance. In this work, one Al 2 O 3 atomic layer coated on the surface of graphite via atomic layer deposition (ALD) process, aiming to construct a stable solid electrode interface and enhance the performance of graphite anode in PIBs. The electrochemical performance analysis shows that the 20 cycles Al 2 O 3 deposited graphite have improved cycle stability of 223 mAh g −1 at 50 mA g −1 after 50 cycles compared with the raw graphite anode of 92 mAh g −1 .