摘要
O3型层状氧化物正极材料NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)具有高比容量、低成本和环境友好性等优点,被认为是最有前途的钠离子电池正极材料之一,但在充放电过程中会发生一系列复杂的相变,导致电化学性能较差。本研究报道了一种协同改性方法,以同时提高NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)正极材料的循环稳定性和倍率性能。通过将硼酸粉末和正极材料固相球磨混匀后低温煅烧,在NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)正极材料表面包覆纳米非金属氧化物B_(2)O_(3)。借助X射线衍射仪(XRD)、扫描电子显微技术(SEM)、透射电子显微镜(TEM)和电化学技术等测试手段,对比分析不同包覆量和原材料的形貌和电化学性能,筛选得到最优包覆量为2%(质量分数,余同)。该方法实现了B_(2)O_(3)的均匀包覆,并且没有改变NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)正极材料的晶体结构。通过电化学性能测试表明2%B_(2)O_(3)包覆材料在1 C倍率下循环200圈容量保持率从78%提升至87%。同时,2%B_(2)O_(3)包覆材料的高倍率性能也得到了改善,10 C高倍率下放电比容量从75 mAh/g提升至99 mAh/g。结果表明,这是一种有效且可靠的表面改性策略,可以增强钠离子电池层状氧化物正极材料的电化学性能。
Due to its high capacity,low cost,and environmental safety,layered oxide O3-NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)is one of the most promising cathode medium recently.However,its complicated phase transitions during the charge-discharge process lead to inferior electrochemical properties.In this study,we report a synergetic modification method to simultaneously increase the rate capacity and cycling stability of the O3-NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)cathode medium by utilizing B_(2)O_(3)-coating and B^(3+)doping.The B_(2)O_(3)-coated NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2) cathode was prepared using the ball milling method.Materials with different B_(2)O_(3) contents were prepared and characterized using X-ray diffractometer,scanning electron microscope,transmission electron microscopy,and electrochemical examinations.The best performing compound was obtained when 2%B_(2)O_(3)coating was utilized.B_(2)O_(3)was uniformly distributed between NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)particles,and the preparation process did not change the crystal structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2).Furthermore,the charge-discharge curves indicated that the capacity retention of 2%B_(2)O_(3)-coated samples was enhanced from 78%to 87%after 200 cycles.B_(2)O_(3)-coated NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)also exhibited remarkable rate capability(99 m Ah/g at a high rate of10 C,compared to 75 m Ah/g for the pristine).These results indicated that the proposed approach is an effective and reliable surface modification strategy for reinforcing the electrochemical properties of layered oxide materials for sodium-ion batteries.
作者
郭凯强
车海英
张浩然
廖建平
周煌
张云龙
陈航达
申展
刘海梅
马紫峰
GUO Kaiqiang;CHE Haiying;ZHANG Haoran;LIAO Jianping;ZHOU Huang;ZHANG Yunlong;CHEN Hangda;SHEN Zhan;LIU Haimei;MA Zifeng(College of Environmental and Chemical Engineering,Shanghai University of Electric Power,Shanghai 200090,China;Zhejiang Na TRIUM Energy Co.Ltd.,Shaoxing 312000,Zhejiang,China;Department of Chemical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2022年第9期2980-2988,共9页
Energy Storage Science and Technology
基金
国家自然科学基金项目(22005190,21938005)
上海市科技启明星计划(20QB1405700)。
