Accordion‐Like Carbon with High Nitrogen Doping for Fast and Stable K Ion Storage

Advanced Energy Materials, Journal Year: 2021, Volume and Issue: 11(41)

Published: Sept. 24, 2021

Abstract Potassium ion battery (PIB) is a potential candidate for future large‐scale energy storage. A key challenge that the (de)potassiation stability of graphitic carbon anodes hampered by limited (002) interlayer spacing. Amorphous with hierarchical structure can buffer volume change during repeated and enable stable cycling. Herein, direct pyrolysis approach demonstrated to synthesize highly nitrogen‐doped (26.7 at.%) accordion‐like anode composed thin nanosheets turbostratic crystalline structure. The endowed self‐assembly process carbonization. accordion enables high reversible capacity 346 mAh g −1 superior cycling stability. This work constitutes general synthesis methodology be used prepare advanced PIBs.

Language: Английский

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Transition Metal (Co, Ni, Fe, Cu) Single‐Atom Catalysts Anchored on 3D Nitrogen‐Doped Porous Carbon Nanosheets as Efficient Oxygen Reduction Electrocatalysts for Zn–Air Battery

Small, Journal Year: 2022, Volume and Issue: 18(34)

Published: July 29, 2022

Abstract Exploring highly active and cost‐efficient single‐atom catalysts (SACs) for oxygen reduction reaction (ORR) is critical the large‐scale application of Zn–air battery. Herein, density functional theory (DFT) calculations predict that intrinsic ORR activity metal SACs follows trend Co > Fe Ni ≈ Cu, in which possess best due to its optimized spin density. Guided by DFT calculations, four kinds transition single atoms embedded 3D porous nitrogen‐doped carbon nanosheets (MSAs@PNCN, M = Co, Ni, Fe, Cu) are synthesized via a facile NaCl‐template assisted strategy. The resulting MSAs@PNCN displays lines with theoretical predictions, SAs@PNCN exhibits ( E 1/2 0.851 V), being comparable Pt/C under alkaline conditions. X‐ray absorption fine structure (XAFS) spectra verify atomically dispersed Co‐N 4 sites catalytically sites. CoN unique contribute outstanding performance SAs@PNCN. Furthermore, catalyst employed as cathode battery, can deliver large power 220 mW cm –2 maintain robust cycling stability over 530 cycles.

Language: Английский

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Engineering Electronic Transfer Dynamics and Ion Adsorption Capability in Dual-Doped Carbon for High-Energy Potassium Ion Hybrid Capacitors

ACS Nano, Journal Year: 2022, Volume and Issue: 16(4), P. 6255 - 6265

Published: March 18, 2022

Sodium and potassium ions energy storage systems with low cost high energy/power densities have recently drawn increasing interest as promising candidates for grid-level applications, while the lack of suitable anode materials fast ion diffusion kinetics highly hinders their development. Herein, we develop a nanoscale confined in situ oxidation polymerization process followed by conventional carbonization treatment to generate phosphorus nitrogen dual-doped hollow carbon spheres (PNHCS), which can realize superior sodium performance. Importantly, density functional theory calculation combined characterizations, e.g., Raman spectroscopy ex X-ray photoelectron spectroscopy, decipher that P/N doping enhance electronic transfer dynamics adsorption capability, are responsible enhanced electrochemical Inspiringly, practicability PNHCS is demonstrated assembling hybrid capacitors (KIHCs), where prominent 178.80 Wh kg-1 at power 197.65 W kg-1, excellent cycling stability, be achieved. This work not only promotes development efficient material sodium/potassium devices but also deciphers embedded mechanism.

Language: Английский

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The Semicoherent Interface and Vacancy Engineering for Constructing Ni(Co)Se₂@Co(Ni)Se₂ Heterojunction as Ultrahigh‐Rate Battery‐Type Supercapacitor Cathode

Advanced Functional Materials, Journal Year: 2022, Volume and Issue: 32(33)

Published: June 1, 2022

Abstract Restricted rate capability is the key bottleneck for large‐scale energy storage of battery‐type supercapacitor cathode due to its sluggish reaction kinetics. Herein, Ni(Co)Se 2 @Co(Ni)Se semicoherent heterojunctions with rich Se vacancies (Vr‐Ni(Co)Se ) as are first constructed. Such a vacancy and heterointerface manipulation can not only essentially regulate electronic structure enhance ions adsorption capability, but also rationalize chemical affinities OH – in diffusion pathway revealed by systematic characterization analysis first‐principle calculations. The as‐prepared delivers large specific capacity 264.5 mAh g –1 at 1 A excellent cycle stability. Surprisingly, it presents ultrahigh retention 159.7 even 250 . Moreover, single phase transition mechanism elucidated systematically using series ex situ techniques. In addition, contributed unique self‐synthesized N/S co‐doped corncob‐derived porous carbon (N/S‐BPC, 316.1 F anode, high‐performance hybrid (HSC) developed, which shows density 68.1 Wh kg 0.75 kW superior performance. findings highlight coordination strategy rational design ultrahigh‐rate HSC cathode, greatly pushing their commercial application processes.

Language: Английский

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Unraveling the Intercorrelation Between Micro/Mesopores and K Migration Behavior in Hard Carbon

Small, Journal Year: 2022, Volume and Issue: 18(12)

Published: Jan. 27, 2022

Abstract Pore‐structure design with increased ion‐diffusion ability is usually regarded as an effective strategy to improve K‐storage performance in hard carbon (HC). However, the relationship between porous structure and K + migration behavior remains unclear requires further exploration. Herein, a series of chemically activated spheres (denoted AHCSs) controllable micro/mesopores are successfully synthesized explore intercorrelation behavior. The experimental results indicate AHCSs have two different storage ways, that is, adsorption at high potential region intercalation process low region. These behaviors closely related pores evolution: micropores afford extra active sites for efficient K‐ions adsorption, therefore positive correlation adsorption‐contributed capacity confirmed; mesopores permit more intercalation/deintercalation by offering adequate pathways, result correlations intercalation‐contributed well initial Coulombic efficiency revealed. All these together contribute achieving excellent reversible capacity, exceptional rate capability ultra‐long cycle lifespan PIBs, simultaneously exhibit energy density considerable cycling stability potassium‐ion full cells. promote fundamental understanding carbon.

Language: Английский

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