Delving into the dissimilarities in electrochemical performance and underlying mechanisms for sodium and potassium ion storage in N-doped carbon-encapsulated metallic Cu_(2)Se nanocubes  

作　　者：Xinyu Wang Yanan Xu Xiaofeng Liu Lei Tan Huaiqiang Gu Xin Du Dan Li 

机构地区：[1]College of Chemistry,Zhengzhou University,Zhengzhou 450001,Henan,China [2]Green Catalysis Center,College of Chemistry,Zhengzhou University,Zhengzhou 450001,Henan,China [3]Institute of Theoretical Physics,Lanzhou University,Lanzhou 730000,Gansu,China [4]School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,Gansu,China [5]Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),College of Chemistry,Nankai University,Tianjin 300071,China [6]State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources,College of Chemistry,Xinjiang University,Urumqi 830046,Xinjiang,China

出　　处：《Journal of Energy Chemistry》2024年第8期336-347,I0008,共13页能源化学（英文版）

基　　金：The Natural Science Foundation of Henan Province(222300420083);the Opening Foundation of State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resource of Xinjiang University(KFKT2021004)。

摘　　要：The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical performance.Herein,metallic Cu_(2)Se encapsulated with N-doped carbon(Cu_(2)Se@NC)was prepared using Cu_(2)O nanocubes as templates through a combination of dopamine polymerization and hightemperature 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 Cu_(2)Se@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 transmission electron microscope(TEM).In particular,the final products in PIBs of K_(2)Se and K_(2)Se_(3)species were determined after discharging,which is different from that in SIBs with the final species of Na_(2)Se.The density functional theory calculation showed that carbon induces strong coupling and charge interactions with Cu_(2)Se,leading to the introduction of built-in electric field on heterojunction to improve electron 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.

关 键 词：Cu_(2)Se nanocubes DFT calculations Ion storage mechanism Potassium ion batteries Sodium ion batteries 

分 类 号：TM912[电气工程—电力电子与电力传动]