文献类型：期刊文献

中文题名：氟掺杂改性LiMn_(0.5)Fe_(0.5)PO_(4)正极材料及其电化学性能

英文题名：Synthesis and modification of F-doped olivine LiFe_(0.5)Mn_(0.5)PO_(4)cathode materials for Li-ion batteries

作者：于松民[1];金洪波[2];杨明虎[3];余海峰[2];江浩[1,2]

机构：[1]华东理工大学材料科学与工程学院超细材料制备与应用教育部重点实验室,上海200237;[2]华东理工大学化工学院上海多级结构纳米材料工程技术研究中心,上海200237;[3]安徽聚合辐化化工有限公司,安徽滁州233200

年份：2024

卷号：43

期号：1

起止页码：302

中文期刊名：化工进展

外文期刊名：Chemical Industry and Engineering Progress

收录：CSTPCD;;EI(收录号：20240715538062);Scopus;北大核心:【北大核心2023】；CSCD:【CSCD2023_2024】；

基金：国家自然科学基金(21975074)。

语种：中文

中文关键词：电化学;磷酸锰铁锂;正极;锂离子电池;氟掺杂;

外文关键词：electrochemistry;lithium iron manganese phosphate(LiMn_(0.5)Fe_(0.5)PO_(4));cathode;lithium-ion battery;F-doping

摘要：目前磷酸铁锂材料由于其较低的能量密度难以满足使用需求。磷酸锰铁锂具有比磷酸铁锂更高的能量密度,同时兼顾磷酸铁锂低成本和晶体结构稳定性的特点。然而缓慢的锂离子扩散动力学和Mn^(3+)引起的Jahn-Teller效应导致材料的循环和倍率性能差,限制了磷酸锰铁锂实际应用。本工作通过引入F离子掺杂,构筑沿b轴取向生长的110nm纳米颗粒磷酸锰铁锂正极材料,探究了它们的基本物理化学性质与电化学性能,发现沿b轴取向生长并暴露的(010)晶面能够显著提升锂离子扩散动力学。此外,F离子引入显著增强了Li—O键以及PO_(4)^(3?)骨架结构,提高锂离子嵌入和脱出过程中晶体结构稳定性。因此,在0.1C和5C电流下,改性磷酸锰铁理正极材料可逆放电比容量分别为153mA·h/g和106mA·h/g。相比于未改性材料,1C循环750次后比容量保持率从90.6%提升到96.4%。
At present,LiFePO_(4)materials is difficult to meet the demand of high energy density.LiMn_(x)Fe_(1?x)PO_(4)(LMFP)cathode materials exhibit higher energy density compared with LiFePO_(4),while maintain the advantage of low cost and high stability of olivine structure.However,the inferior rate and cycle performance limit its practical application,which is ascribed by poor Li-ion diffusion kinetic and Jahn-Teller effect of Mn^(3+).In this work,a F-doping strategy was proposed to construct 110nm nanoparticles of LMFP with highly ordered b-axis orientation.The basic physicochemical properties and electrochemical properties of materials were explored,finding that the exposed(010)crystal face acted as Li-ion diffusion channel can significantly improve the Li-ion transport efficiency,while the doped F ions can increase the Li—O bond distance and the PO43?binding energy to enhance the stability of crystal structure.Therefore,the reversible specific discharge capacity of the F-doped LMFP was 153mA·h/g and 106mA·h/g at 0.1C and 5C,respectively.After 750 cycles at 1C,the capacity retention increased from 90.6%to 96.4%compared with the unmodified material.