首页|Delving into the dissimilarities in electrochemical performance and underlying mechanisms for sodium and potassium ion storage in N-doped carbon-encapsulated metallic Cu2Se nanocubes

Delving into the dissimilarities in electrochemical performance and underlying mechanisms for sodium and potassium ion storage in N-doped carbon-encapsulated metallic Cu2Se nanocubes

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The large volumetric variations experienced by metal selenides within conversion reaction result in infe-rior rate capability and cycling stability,ultimately hindering the achievement of superior electrochem-ical performance.Herein,metallic Cu2Se encapsulated with N-doped carbon(Cu2Se@NC)was prepared using Cu2O nanocubes as templates through a combination of dopamine polymerization and high-temperature selenization.The unique nanocubic structure and uniform N-doped carbon coating could shorten the ion transport distance,accelerate electron/charge diffusion,and suppress volume variation,ultimately ensuring Cu2Se@NC with excellent electrochemical performance in sodium ion batteries(SIBs)and potassium ion batteries(PIBs).The composite exhibited excellent rate performance(187.7 mA h g-1 at 50 A g-1 in SIBs and 179.4 mA h g-1 at 5 A g-1 in PIBs)and cyclic stability(246.8 mA h g-1 at 10 A g-1 in SIBs over 2500 cycles).The reaction mechanism of intercalation combined with conversion in both SIBs and PIBs was disclosed by in situ X-ray diffraction(XRD)and ex situ trans-mission electron microscope(TEM).In particular,the final products in PIBs of K2Se and K2Se3 species were determined after discharging,which is different from that in SIBs with the final species of Na2Se.The density functional theory calculation showed that carbon induces strong coupling and charge inter-actions with Cu2Se,leading to the introduction of built-in electric field on heterojunction to improve elec-tron mobility.Significantly,the theoretical calculations discovered that the underlying cause for the relatively superior rate capability in SIBs to that in PIBs is the agile Na+diffusion with low energy barrier and moderate adsorption energy.These findings offer theoretical support for in-depth understanding of the performance differences of Cu-based materials in different ion storage systems.

Cu2Se nanocubesDFT calculationsIon storage mechanismPotassium ion batteriesSodium ion batteries

Xinyu Wang、Yanan Xu、Xiaofeng Liu、Lei Tan、Huaiqiang Gu、Xin Du、Dan Li

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College of Chemistry,Zhengzhou University,Zhengzhou 450001,Henan,China

Green Catalysis Center,College of Chemistry,Zhengzhou University,Zhengzhou 450001,Henan,China

Institute of Theoretical Physics,Lanzhou University,Lanzhou 730000,Gansu,China

School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,Gansu,China

Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),College of Chemistry,Nankai University,Tianjin 300071,China

State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources,College of Chemistry,Xinjiang University,Urumqi 830046,Xinjiang,China

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Natural Science Foundation of Henan ProvinceOpening Foundation of State Key Laboratory of Chemistry and Utilization of Carbonbased Energy Resource of Xinjiang Universit

222300420083KFKT2021004

2024

10.1016/j.jechem.2024.03.056

能源化学
中国科学院大连化学物理研究所 中国科学院成都有机化学研究所

能源化学

CSTPCDEI
影响因子：0.654
ISSN：2095-4956
年,卷(期)：2024.95(8)