Tailored Supramolecular Self-Assembly Nanoporous Carbon Toward Zinc Ion Hybrid Supercapacitor Application.

Abstract

Zinc ion hybrid supercapacitors (ZIHCs), newly emerging energy storage devices, hold great potential for future energy storage applications. Proper design of porous cathode (c.a. porous carbon) to achieve efficient storage of hydrated Zn(H₂O)₆ ²⁺ ions is one of the keys to improving its capacitive performance. However, although various strategies have been proposed to balance cost and performance, developing a carbon cathode synthesis strategy that concurrently optimizes both cost-effectiveness and efficiency remains nontrivial. Herein, to address this challenge, an innovative cost-acceptable supramolecular self-assembly strategy is explored to synthesize a molecular sieve type nanoporous carbon with reinforced nitrogen doping capability. In virtue of inventive "twin template" method, supramolecules in heavy bio-oil undergo targeted polycondensation and stack to form carbon fibers mesh with uniform nanopores around 10 Å. The DFT calculation confirmed its rapid transport of hydrated Zn(H₂O)₆ ²⁺ ions. Concurrently, the in situ conversion of specific oxygenic groups in this scheme reveals an ideal reaction pathway for reinforced heteroatom functionalization. The KAc-MgCit-NPC sample with reinforced nitrogen doping exhibits a remarkable energy density increase of over 34%. This work opens a new avenue for developing high-performance carbon materials towards ZIHCs applications.