Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by Selective Nucleophilic Substitution of Phosphorus  

作　　者：Se In Kim Woong-Ju Kim Jin Gu Kang Dong-Wan Kim 

机构地区：[1]School of Civil,Environmental and Architectural Engineering,Korea University,02841 Seoul,South Korea [2]Nanophotonics Research Center,Korea Institute of Science and Technology,02792 Seoul,South Korea

出　　处：《Nano-Micro Letters》2024年第10期618-637,共20页纳微快报（英文版）

基　　金：supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF);funded by the Ministry of Education(2020R1A6A1A03045059);by Ministry of Science and ICT(2022R1A2C3003319);by the Institutional Program(2E33221)of the Korea Institute of Science and Technology(KIST).

摘　　要：Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy storage.Herein,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery anodes.Via thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal structure.Further,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H tetrahedra.The resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H vacancies.The doping concentrations are varied by controlling the amount of precursors or their mean free paths.Even at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 cycles.These improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state diffusion.The approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关 键 词：Li-ion battery Two-dimensional N-type siloxene Doping mechanism KINETICS 

分 类 号：TM912[电气工程—电力电子与电力传动]