P2型层状氧化物正极的人工界面层构筑及储钠性能??????????
Artificial interface layer construction and sodium storage performance of P2-type layered oxide cathode
刘杰 1石雪茹 1魏树兵 1曹鑫鑫1
作者信息
- 1. 中南大学材料科学与工程学院,湖南长沙 410083
- 折叠
摘要
P2型Na2/3Ni1/3Mn2/3O2(P2-NNMO)工作电压高、安全性好、成本低,是有潜力的钠离子电池正极材料.针对P2-NNMO正极钠不足和P2-NNMO正极与电解液的界面问题,通过化学预钠化法(P2-NNMO正极和联苯钠的自发反应),构造了一种富含无机物的人工界面层,可使外源性的钠嵌入氧化物正极层间.结果表明:预钠化形成的人工界面层含有的NaF,可有效缓解正极材料被有机溶剂侵蚀及过渡金属的溶出;同时人工界面层也改善了钠离子的扩散动力学.改性后的正极(P2-NNMO@CEI)在电压为2～4 V、电流密度为20 mA/g的条件下,放电比容量为95.1 mA∙h/g、首次库伦效率为88.5%;在50 mA/g下循环280次后容量保持率为84.2%.该研究为层状氧化物正极表面改性提供了一种有效方法,也为电极材料的界面设计提供了新的思路和方向.
Abstract
P2-type Na2/3Ni1/3Mn2/3O2(P2-NNMO)has high working voltage,good safety,and low cost,making it a promising cathode material for sodium ion batteries.To solve the problem of sodium deficiency of P2-NNMO cathode and the interface between P2-NNMO cathode and electrolyte,an inorganic-rich artificial interface layer was constructed on P2-NNMO cath-ode via a chemical pre-sodiation method(spontaneous redox reaction between P2-NNMO cathode and sodium biphenyl),with which extra sodium ions insert the oxide cathode host structure.The results showed that the artificial interface layer formed by pre-sodiation contained NaF,shielded cathode material solvent corrosion and transition metal dissolution,and im-proved the diffusion kinetics of Na+.The modified cathode(P2-NNMO@CEI)delivered the discharge specific capacity of 95.1 mA∙h/g and the coulombic efficiency of 88.5%within the voltage of 2～4 V at the current density of 20 mA/g and pos-sessed capacity retention of 84.2%after 280 cycles at the current density of 50 mA/g.This study provided an effective method for surface modification of layered oxide cathode and further provided a new concept and direction for designing in-terfaces of electrode materials toward real applications.
关键词
正极电解液界面/循环稳定性/层状氧化物/钠离子电池Key words
cathode electrolyte interface/cycling stability/layered oxides/sodium ion batteries引用本文复制引用
基金项目
国家自然科学基金项目(52002407)
国家自然科学基金项目(51932011)
湖南省科技创新计划项目(2022RC1078)
出版年
2024
NETL
NSTL
万方数据