Nature Communications (May 2024)

Electrochemical-repaired porous graphene membranes for precise ion-ion separation

  • Zongyao Zhou,
  • Kangning Zhao,
  • Heng-Yu Chi,
  • Yueqing Shen,
  • Shuqing Song,
  • Kuang-Jung Hsu,
  • Mojtaba Chevalier,
  • Wenxiong Shi,
  • Kumar Varoon Agrawal

DOI
https://doi.org/10.1038/s41467-024-48419-6
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 11

Abstract

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Abstract The preparation of atom-thick porous lattice hosting Å-scale pores is attractive to achieve a large ion-ion selectivity in combination with a large ion flux. Graphene film is an ideal selective layer for this if high-precision pores can be incorporated, however, it is challenging to avoid larger non-selective pores at the tail-end of the pore size distribution which reduces ion-ion selectivity. Herein, we develop a strategy to overcome this challenge using an electrochemical repair strategy that successfully masks larger pores in large-area graphene. 10-nm-thick electropolymerized conjugated microporous polymer (CMP) layer is successfully deposited on graphene, thanks to a strong π-π interaction in these two materials. While the CMP layer itself is not selective, it effectively masks graphene pores, leading to a large Li+/Mg2+ selectivity from zero-dimensional pores reaching 300 with a high Li+ ion permeation rate surpassing the performance of reported materials for ion-ion separation. Overall, this scalable repair strategy enables the fabrication of monolayer graphene membranes with customizable pore sizes, limiting the contribution of nonselective pores, and offering graphene membranes a versatile platform for a broad spectrum of challenging separations.