Coupling Uniform Pore Size And Multi‑Chemisorption Sites: Hierarchically Ordered Porous Carbon For Ultra-Fast And Large Zinc Ion Storage

Abstract

Constructing hierarchically ordered macro/meso−microporous structures of carbonaceous cathode with matchable pore size and adequate active sites is significant toward large Zn²⁺ storage, but remains a formidable challenge. Herein, a new perspective is reported for synthesizing phosphorus and nitrogen dual-doped hierarchical ordered porous carbon (PN-HOPC) by eliminating the micropore confinement effect and synchronously introducing multi-chemisorption sites. The interconnected macropore can effectively facilitate long-distance mass transfer, and meso−microporous wall can promote accessibility of active sites. Density functional theory (DFT) calculations identify that the P and N co-doping markedly contributes to the reversible adsorption/desorption of zinc ions and protons. Consequently, the optimized PN-HOPC exhibits outstanding Zn²⁺ storage capabilities in terms of high capacity (211.9 mAh g⁻¹), superb energy density (169.5 Wh kg⁻¹), and ultralong lifespan (99.3% retention after 60 000 cycles). Systematic ex situ measurements integrating with in situ Raman spectroscopy and electrochemical quartz crystal microbalance (EQCM) techniques elucidate that the superior electrochemical capability is ascribed to the synergistic effect of the Zn²⁺, H⁺, and SO₄²⁻ co-adsorption mechanism, as well as invertible chemical adsorption. This study not only provides new insights to design advanced carbon materials toward practical applications but also sheds lights on a deeper understanding of charge storage mechanism for zinc-ion capacitors (ZICs).