Nanoarchitectonics with Compression-Confinement activation of bamboo carbon for High-Rate aqueous supercapacitors

Valorizing bamboo-derived carbon into high-value porous electrodes remains challenging for high-rate aqueous supercapacitors, because conventional activation tends to widen pores and strip heteroatoms, whereas densification often sacrifices ion accessibility. Here we introduce a nanoarchitectonics compression-confinement activation concept that addresses this tension by regulating mass-transport and reaction kinetics through mechanical processing, without changing the activator chemistry. Compacting a bamboo carbon/melamine/potassium acetate precursor prior to pyrolysis creates a diffusion-limited microenvironment that broadens and delays volatile release, sustains gas-solid contact, and mitigates nitrogen volatilization. As a result, activation likely proceeds through a more uniform sub-nanometer etching process while stabilizing nitrogen, with pyrrolic-N enrichment under confinement. The optimized sample (700-20 T-N) delivers a high surface area with a balanced micro/mesopore distribution (∼72/28) and enriched pyrrolic-N, achieving 472.8F g^-1 or 580F cm^-3 at 0.5 A g^-1 in 6 M KOH, with 79.7% retention at 10 A g^-1 and 95.4% after 6000 cycles. A symmetric device further reaches an energy density of 14.09 Wh kg^-1 at 500 W kg^-1 and maintains 88.6% capacitance after 5000 cycles. In situ TG-FTIR/MS shows that compression is associated with delayed and broadened evolved-gas profiles and substantially suppressed nitrogen loss, supporting the interpretation that mechanical confinement induces a diffusion-limited activation environment correlated with ultramicropore enrichment and pyrrolic-N preservation. This mechanically mediated route provides a simple biomass-based framework with scale-up potential for converting bioresources into high-rate carbon electrodes.