Extended “Adsorption–Insertion” Model: A New Insight into the Sodium Storage Mechanism of Hard Carbons

Abstract Hard carbons (HCs) are promising anodes of sodium‐ion batteries (SIBs) due to their high capacity, abundance, and low cost. However, the sodium storage mechanism of HCs remains unclear with no consensus in the literature. Here, based on the correlation between the microstructure and Na storage behavior of HCs synthesized over a wide pyrolysis temperature range of 600–2500 °C, an extended “adsorption–insertion” sodium storage mechanism is proposed. The microstructure of HCs can be divided into three types with different sodium storage mechanisms. The highly disordered carbon, with d 002 (above 0.40 nm) large enough for sodium ions to freely transfer in, has a “pseudo‐adsorption” sodium storage…

• NS
  National Science Foundation
• NN
  National Natural Science Foundation of China

  Awards: 51572011, 51372268
• BM
  Beijing Municipal Science and Technology Commission

  Award: Z181100004718007
• NK
  National Key Research and Development Program of China

  Awards: 2017YFB0102204, 2016YFB0100400