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 .