Collapsed N&S dual-doped carbon nanocages as high-density anode for ultrahigh volumetric performance of Li-ion batteries

Compact lithium-ion batteries for miniaturized devices require high-volumetric-performance anodes. Either the graphite with high density or the porous nanocarbons with high gravimetric performance is limited in volumetric performance. Herein, we construct a series of anode materials, i.e. the collapsed carbon nanocages with different dopants, by capillarity compression, which achieves a high density of ∼0.97 g cm⁻³ but remains abundant micropores with increased active sites and enlarged interlayer distance. The N&S dual-doping redistributes the charges of sp² carbon to an optimal status, leading to the high Li-ion capacity, meanwhile facilitates the wettability at the electrode/electrolyte interface, leading to the enhanced Li-ion diffusion coefficient. Accordingly, the collapsed N&S dual-doped carbon nanocages (cNSCNC) anode exhibits a record-high volumetric capacity of 1578 mAh cm⁻³ at 0.1 A g⁻¹, excellent rate capability and cycling stability, thus achieving an ultrahigh volumetric energy density of 1087 Wh L⁻¹ at 120 W L⁻¹ for the cNSCNC//LiFePO₄ full cell.