(A) Schematic diagram of the synthesis process of MS-HMCMs. Reproduced with permission from Ref. [71]. Copyright©2024, Elsevier Ltd. SEM images of (B) single-shelled HCNs (1S-HCNs), (C) double-shelled HCNs (2S-HCNs), (D) three-shelled HCNs (3S-HCNs), and (E) four-shelled HCNs (4S-HCNs), respectively. The insets are their TEM images. Reproduced with permission from Ref. [72]. Copyright©2018, Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim. (F) Rate capabilities of SHCS and DHCS electrodes. (G) Cycle performance of SHCS and DHCS electrodes under 0.6 A g⁻¹. (F, G) Reproduced with permission from Ref. [73]. Copyright©2020, Elsevier Ltd. (H) Schematic of the synthesis steps for DHCSs and N-DHCSs. (I) High-magnification TEM image of the as-obtained N-DHCSs. (J) Low-magnification high-resolution TEM (HRTEM) image of the as-obtained N-DHCSs and simulated pattern inset. (H–J) Reproduced with permission from Ref. [74]. Copyright©2015, Elsevier Ltd. (K) Schematic illustration for the unique feature of DHNCNs-900 as anode material in SIBs. Reproduced with permission from Ref. [75]. Copyright©2024, Elsevier Ltd.