Acid-Assisted Exfoliation toward Metallic Sub-nanopore TaS₂ Monolayer with High Volumetric Capacitance

Abstract

Conductive porous structures are favorable as active electrode materials for energy storage by boosting the active sites and specific surface area but have been rarely achieved in transition metal dichalcogenides. Here, we developed acid-assisted exfoliation for the first time, to successfully exfoliate TaS into very large-sized conductive monolayers with controllable in-plane sub-nanopores. By inducing both interlayer lattice expansion and basal in-plane etching, hydrogen ion, previously regarded disastrous in charged system, was creatively utilized as an efficient and easily accessible assistant in simultaneous exfoliation and controllable structural modification. Benefiting from pore size (∼0.95 nm) matching well with electrolyte ion size, coexistence of ultrahigh conductivity and fast ion transport was achieved in metallic large-sized monolayers. Notably, the as-produced TaS-based electrode delivers large volumetric capacitance (508 F/cm at scan rate of 10 mV/s) and high energy density (58.5 Wh/L) when fabricated into a micro-supercapacitor. We anticipate acid-assisted exfoliation to be a promising strategy in constructing 2D nanomaterials with novel structure for wide energy applications.

2D Metallic Transitional Metal Dichalcogenides for Electrochemical Hydrogen Evolution

“…Recently, high‐quality ultrathin MTMDCs obtained by liquid‐phase exfoliations have been proved to be perfect platforms for exploring novel physical properties (e.g., superconductivity) and engineering versatile applications in catalytic HER and supercapacitor . Huang and co‐workers obtained monolayer 2H‐TaS 2 nanosheets through chemical exfoliation using n‐butyl lithium .…”

“…Subsequently, based on this exfoliation method, large size TaS 2 monolayers with subnanopores were also produced through acid pretreatment before exfoliation . The pore density of TaS 2 monolayers was precisely controlled by tuning the H + concentration.…”

“…Later on, the improved chemical exfoliation approaches through alkali metal intercalations afforded monolayer or few‐layer MTMDC nanosheets with micrometer sizes . Such 2D MTMDC layers have revealed tremendous application potentials as catalysts in hydrogen evolution reaction (HER) and as electrode materials in supercapacitors . The colloidal synthesis route has presented great advantages, such as scalability, easy operation, and high yield.…”

Miniaturized Energy Storage Devices Based on Two‐Dimensional Materials

“…proposed as trategy to exfoliate Ta S 2 into large-sized, conductive monolayersw ith in-plane nanopores. [136] The metallics ub-nanopore Ta S 2 (MSP-TaS 2 )m onolayers were synthesized by means of acid-assisted exfoliation of LiTaS 2 singlec rystals. Ta king advantage of the fast and mild etchingp roperties of H + ,a ne fficient simultaneous exfoliation and structural modification of Ta S 2 was conducted.…”

From Lead Iodide to a Radical Form Lead‐Iodide Superlattice: High Conductance Gain and Broader Band for Photoconductive Response

“…Two-dimensional (2D) layered materials,s uch as graphene, molybdenum disulfide,a nd metal-organic frameworks (MOFs), [1] have unique physical and chemical properties and many potential applications in electronics, [2] biomedicine, [3] electrochemical energy storage, [4] chemical sensing/ biosensing, [5] and catalysis. [6] Inserting them with neutral alkali metal, alkaline earth, rare earth or organic groups can yield intercalation compounds cohered by van der Waals interactions,t he so-called superlattices, [7] which offers new opportunities to modify optical and electrical properties of the host 2D material.…”