Introducing pore into carbon materials can improve potassium storage capacity due to the abundance of active sites. However, unsuitable pores, especially micropores, restrict the fast storage of potassium ions. Thus, pore
structure engineering in carbon is essential but challenging for the kinetics of fast potassium storage. Herein, we report a general “pore expanding” strategy by the
in-situ pulverization-reaggregation technology of basic carbonate to achieve
accurate pore width adjustment and carbon structure modulation. And this strategy also applies to many pitch/basic carbonates (e.g., pitch/basic magnesium carbonate, pitch/basic zinc carbonate, pitch/basic nickel carbonate and pitch/basic
cupric carbonate), showing controlled adjustment of pore width. Taking pitch/basic magnesium carbonate as an example, the pores of carbon nanosheets (CNS) can be tuned from 5 nm to 9.3 nm by the formation and orientation aggregation of MgO nanoparticles. Benefiting from the expansion of pores and the generation of rich defects, the material achieves high capacity (417.6 mAh g
-1 at 0.1 A g
-1) and high rate performance (147 mAh g
-1 at 2A g
-1). This study provides a general strategy for the pore structure engineering in carbon materials and offers mechanism insights for fast potassium storage in carbon materials.