High Areal Capacity Anode Enabled by Enhanced Charge Transport on Self‐Supported Spindle‐Like Carbon Nanofiber Architecture of CTAB‐Treated Geothermal Silica Waste

Abstract High areal‐capacity anodes are crucial for compact and energy‐dense lithium‐ion batteries. Nevertheless, thick slurry cast on current collectors often leads to sluggish charge transport and poor cycle stability. This study addresses these issues by developing self‐supported spindle‐like silica‐carbon nanofiber architectures via electrospinning. Cetyltrimethylammonium bromide (CTAB) surfactant is employed to modify the surface potential of geothermal silica waste nanoparticles, enhancing their dispersibility in electrospinning solution and producing fully encapsulated silica nanoparticles within spindle‐like carbon nanofibers (SiO 2 ‐CTAB@CNF). Unlike thick slurry‐based designs, spindle‐like structures can serve as spacers, creating efficient pathways for electrolyte infiltration across the anode thickness. Consequently, SiO 2 ‐CTAB@CNF balances optimal porosity (34 %) toward high active material loading (9.5 mg cm −2 ), establishing low tortuosity ( : 2) and high coefficient of diffusivity. The half‐cell SiO 2 ‐CTAB@CNF battery delivers a notable areal discharge capacity of 4 mAh cm −2 , meeting commercial high‐areal capacity targets. The full‐cell SiO 2 ‐CTAB@CNF||LFP achieves high discharge capacity of 3.6 mAh cm −2 at 0.1 mA cm −2 . Even under higher areal current value (0.3 mA cm −2 ), the full‐cell battery can deliver capacity of 2.58 mAh cm −2 and remain stable after 100 cycles. This work highlights the use of advanced nanostructures and geothermal silica waste to produce sustainable and high‐areal capacity lithium‐ion batteries.