摘要
Perovskite fluorides with three-dimensional skeletal structures have received extensive attention due to their high theoretical capacity as battery anodes.However,wide bandgap-induced low electronic conductivity and sluggish lithium-ion transport hinder their electrochemical reversibility.Herein,taking perovskite fluorides NaMF_(3)(M from Mn,Ni,Co,Mg,Fe)as the research object,an entropy-mediated strategy is proposed to fundamentally enhance the carrier transport kinetics and electrochemical stability.Theoretical calculations show that the increased configurational entropy of NaMF_(3)can induce the transformation from insulator or semiconductor or half-metal to metal conductor,thereby greatly improving electronic conductivity.Moreover,the high-entropy NaMF_3 anode exhibits outstanding lithium-ion diffusion kinetics with significant pseudocapacitive reaction characteristics due to abundant active sites and expandable unit cell volume.Therefore,high-entropy NaMF_3 anode demonstrates outstanding lithium storage performance with a high reversible capacity of 571 mAhg^(-1)at 0.1 A g^(-1),superior rate capability of 266 mAhg^(-1)at 3.2 Ag^(-1),and predominant cycle stability of 165 mAhg^(-1)after 1000 cycles at 2.0 Ag^(-1).Importantly,the lithium storage conversion mechanism and corresponding electrochemical contribution of metal elements have been elucidated for high-entropy NaMF_(3) anode.This work provides a new idea for designing perovskite fluorides as lithium-ion battery materials.
基金
supported by the Natural Science Foundation of Shandong(ZR2020KB011,ZR2024MB062,ZR2024QB321)
the National Natural Science Foundation of China(22379082,22409109)
the Taishan Scholars Program(tsqn201909119)。
