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Co 3 Se 4 Quantum Dots as an Ultrastable Host Material for Potassium‐Ion Intercalation
Author(s) -
Hussain Nadeem,
Li Maoxin,
Tian Bingbing,
Wang Haihui
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202102164
Subject(s) - materials science , intercalation (chemistry) , lithium (medication) , electrochemistry , anode , ion , chemical engineering , quantum dot , nanotechnology , transmission electron microscopy , nanostructure , redox , potassium , electrode , inorganic chemistry , chemistry , medicine , engineering , metallurgy , endocrinology , physics , quantum mechanics
Abstract Potassium‐ion batteries (KIBs) are receiving increased attention due to their cost‐effective and similar energy‐storage mechanism to lithium‐ion batteries. However, the lack of appropriate electrode materials is still hampered for their development, which is mainly caused by the large size of the potassium ions (1.38 Å) including low structural stability and poor electrochemical redox reaction kinetics. Herein, Co 3 Se 4 quantum dots (QD) encapsulated by N‐doped carbon (CSC) are reported as an anode material for KIBs, in which a morphology change process occurs. Benefiting from the unique uniform nanostructure reducing the ion‐diffusion length, the improved electronic conductivity, and the enhanced protective effect of N‐doped carbon (NC) alleviating volume fluctuation, the CSC demonstrates excellent electrochemical performance. The core–shell‐like CSC composite demonstrates remarkable discharge capacity (410 mA h g −1 at 0.1 A g −1 after 550 cycles, 360 mA h g −1 at 0.5 A g −1 after 3200 cycles) and excellent cyclic performance over 10 000 cycles at 1 A g −1 . Density functional theory calculations show a larger reaction energy of Co 3 Se 4 QD than bulk Co 3 Se 4 , a lower barrier of K atom migration in Co 3 Se 4 QD than bulk Co 3 Se 4 , and also favor the intercalation reaction rather than replacement reaction. In situ X‐ray diffraction and ex situ transmission electron microscopy are further used to evaluate potassiation/depotassiation phenomena.