A facile ice-templating-induced puzzle coupled with carbonization strategy for kilogram-level production of porous carbon nanosheets as high-capacity anode for lithium-ion batteries

Two-dimensional porous carbon nanosheets (PCNSs) are considered promising anodes for lithium-ion batteries due to their synergetic features arising from both graphene and porous structures. Herein, using naturally abundant and biocompatible sodium humate (SH) as the precursor, PCNSs are prepared from the laboratory scale up to the kilogram scale by a method of a facile ice-templating-induced puzzle coupled with a carbonization strategy. Such obtained SH-derived PCNSs (SH-PCNSs) possess a hierarchical porous structure dominated by mesopores having a specific surface area (~127.19 ² g⁻¹), pore volume (~0.134 cm³ g⁻¹), sheet-like morphology (~2.18 nm in thickness), and nitrogen/oxygen-containing functional groups. Owing to these merits, the SH-PCNSs present impressive Li-ion storage characteristics, including high reversible capacity (1011 mAh g⁻¹ at 0.1 A g⁻¹), excellent rate capability (465 mAh g⁻¹ at 5 A g⁻¹), and superior cycle stability (76.8% capacitance retention after 1000 cycles at 5 A g⁻¹). It is noted that the SH-PCNSs prepared from the kilogram-scale production procedure possess comparable electrochemical properties. Furthermore, coupling with a LiNi_1/3Co_1/3Mn_1/3O₂ cathode, the full cells deliver a high capacity of 167 mAh g⁻¹ at 0.2 A g⁻¹ and exhibit an outstanding energy density of 128.8 Wh kg⁻¹, highlighting the practicability of this porous carbon nanosheets and the potential commercial opportunity of the scalable processing approach.