Synthesis of Alumina‐Coated Natural Graphite for Highly Cycling Stability and Safety of Li‐Ion Batteries

Summary of main observation and conclusion The natural graphite (NG) uniformly coated with alumina ceramics (Al 2 O 3 ) was successfully synthesized through sol‐gel method. The aluminum plastic film soft‐packed battery prepared using Al 2 O 3 ‐coated NG as anode material exhibits excellent cycle performance and safety performance. The cycling retention of AN‐1 is 84.95% after 200 cycles at a rate of 1 C in a potential window ranging from 3.0 to 4.35 V, which is much greater than 75.07% of NG under the same test conditions. The result of the nail penetration tests shows that the successful nail penetration rate of the NG used as anode is 0%, while that of Al 2 O 3 coated samples AN‐1 is 100%. The test results show that the Al 2 O 3 coating could act as a solid electrolyte to suppress side reactions, improve cycle stability, and prevent a thermal runaway under mechanical abuse.