From melamine-resorcinol-formaldehyde to nitrogen-doped carbon xerogels with micro- and meso-pores for lithium batteries

Novel multi-scaled porous nitrogen-doped carbon is synthesized by enriching the simple resorcinol-formaldehyde xerogel method with: (a) addition of melamine for nitrogen-doping and micron-duct formation; (b) incorporation of PEO-PPO-PEO micelles for the optimization of the duct percolation; and (c) integration of CO₂-etching into the carbonization process for the formation of abundant 2 nm pores. Our experimental results confirm that these nitrogen-doped carbon xerogels (NCXs) indeed comprise a multi-scaled porous structure having nano-porous carbon in a network of micron-size percolated hollow-channels. NCXs prepared by CO₂-etching at 950 °C for 8 hours have a high surface area of 2912 m² g^-1. In addition, the lithium ion batteries fabricated using these NCXs show a high specific capacity of 645 mA h g^-1, with excellent cycle stability and good rate capability.