CO 2 ‐Etching Creates Abundant Closed Pores in Hard Carbon for High‐Plateau‐Capacity Sodium Storage

Abstract Hard carbon (HC) has become the most promising anode material for sodium‐ion batteries (SIBs), but its plateau capacity at ≈0.1 V (Na + /Na) is still much lower than that of graphite (372 mAh g −1 ) in lithium‐ion batteries (LIBs). Herein, a CO 2 ‐etching strategy is applied to generate abundant closed pores in starch‐derived hard carbon that effectively enhances Na + plateau storage. During CO 2 etching, open pores are first formed on the carbon matrix, which are in situ reorganized to closed pores through high‐temperature carbonization. This CO 2 ‐assisted pore‐regulation strategy increases the diameter and the capacity of closed pores in HC, and simultaneously maintains the microsphere morphology…

• NN
  National Natural Science Foundation of China

  Award: 22279122
• SS
  Shenzhen Science and Technology Innovation Program

  Award: JCYJ20220530162402005
• NS
  Natural Science Foundation of Zhejiang Province

  Award: LZ22B030004