Commercializable Fluorine-Doped Porous Carbon Toward Advanced 4.5 V-Class Lithium-Ion Capacitors

Abstract

Low specific capacitances and/or limited working potential (≤4.5 V). of the prevalent carbon-based positive electrodes as the inborn bottleneck seriously hinder practical advancement of lithium-ion capacitors. Thus, breakthroughs in enhancement of both specific capacitances and upper cutoff potentials are enormously significant for high-energy density lithium-ion capacitors. Herein, we first meticulously design and scalably fabricate a commercializable fluorine-doped porous carbon material with competitive tap density, large active surface, appropriate aperture distribution, and promoted affinity with the electrolyte, rendering its abundant electroactive inter-/surface and rapid ${\mathrm{PF}}_6^{-}$ transport. Theoretical calculations authenticate that fluorine-doped porous carbon possesses lower ${\mathrm{PF}}_6^{-}$ adsorption energy and stronger interaction with ${\mathrm{PF}}_6^{-}$. Thanks to the remarkable structural/compositional superiority, when served as a positive electrode toward lithium-ion capacitors, the commercial-level fluorine-doped porous carbon showcases the record-breaking electrochemical properties within a wider working window of 2.5–5.0 V (vs Li/Li⁺) in terms of high-rate specific capacitances and long-duration stability, much superior to commercial activated carbon. More significantly, the 4.5 V-class graphite//fluorine-doped porous carbon lithium-ion capacitors are first constructed and manifest competitive electrochemical behaviors with long-cycle life, modest polarization, and large energy density. Our work provides a commendable positive paradigm and contributes a major step forward in next-generation lithium-ion capacitors and even other high-energy density metal-ion capacitors.