fig4
Figure 4. (A) SEM image and cycling stability of 3D-HPCS[70]. Copyright 2021, Elsevier; (B) SEM image and cycling stability of NOCNBs[71]. Copyright 2020, Elsevier. 3D-HPCS: Three-dimensional porous carbon scaffold; NOCNBs: active sites-enriched hard carbon porous nanobelts; SEM: scanning electron microscope.
