富锂层状氧化物是构筑高能量密度锂离子电池富有潜力的正极材料.然而,由于不可逆的结构变化和缓慢的界面动力学,传统的多晶富锂层状氧化物正极材料循环和倍率性能较差.本文提出了一种聚乙烯基吡咯烷酮(PVP-K30)辅助共沉淀制备单晶Li_(1....富锂层状氧化物是构筑高能量密度锂离子电池富有潜力的正极材料.然而,由于不可逆的结构变化和缓慢的界面动力学,传统的多晶富锂层状氧化物正极材料循环和倍率性能较差.本文提出了一种聚乙烯基吡咯烷酮(PVP-K30)辅助共沉淀制备单晶Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)纳米片的方法.这种方法操作简单、成本低且便于放大生产.所制备的单晶纳米片内部晶格连续且无晶界,缩短了Li+的嵌入/脱嵌路径,加快了电极反应动力学过程.单晶结构还能抑制层状相向尖晶石相的不可逆相变和颗粒内部裂纹的形成,起到稳定层状结构的作用.电化学测试结果表明,所制备的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)单晶纳米片在0.1 C倍率下的可逆容量为254.5 mA h g^(-1),在5 C高倍率下循环1000次后容量保持率为71.9%.这种简单的制备纳米片单晶材料的方法为提高富锂层状氧化物正极材料的循环性能和倍率性能提供了新的思路.展开更多
Consisting of one to a few atomic layers,two-dimensional(2D)materials have atomically perfect surfaces that are free of dangling bonds and exhibit various exotic physical and chemical properties.Even more exciting,one...Consisting of one to a few atomic layers,two-dimensional(2D)materials have atomically perfect surfaces that are free of dangling bonds and exhibit various exotic physical and chemical properties.Even more exciting,one can construct new materials by stacking different 2D layers as they are generally bonded by van der Waals interactions.Therefore,in the past decade,2D materials have attracted much interest in the field of materials science,physics,chemistry and electrical/optical engineering.To implement the most anticipated applications of the 2D materials-based devices in the future,the growth of large-scale 2D single crystals is a prerequisite.Only single crystals can ensure the ultimate intrinsic performance of the materials and the uniformity of the devices.展开更多
单晶Si,Si C,α-Al2O3,Li Ta O3等是制作半导体晶圆的常用功能材料,晶圆的精密加工多采用工件自旋转平面磨削(RISG)。RISG不同于传统的往复平面磨削,相互接触的砂轮和晶圆绕各自轴线旋转,依靠砂轮的轴向进给磨削。本文介绍了RISG加工的...单晶Si,Si C,α-Al2O3,Li Ta O3等是制作半导体晶圆的常用功能材料,晶圆的精密加工多采用工件自旋转平面磨削(RISG)。RISG不同于传统的往复平面磨削,相互接触的砂轮和晶圆绕各自轴线旋转,依靠砂轮的轴向进给磨削。本文介绍了RISG加工的原理及磨粒运动的数学模型,分析了磨纹密度、倾斜角、系统刚度等因素对RISG加工晶圆的平面度和表面粗糙度的影响,并通过分析磨削力探索RISG的材料去除机理,展望了晶圆加工的研究方向。展开更多
基金supported by the National Natural Science Foundation of China (22121005, 22020102002 and 21835004)the Frontiers Science Center for New Organic Matter of Nankai University (63181206)Tianjin Lishen New Energy Technology Co., Ltd. for financial support。
文摘富锂层状氧化物是构筑高能量密度锂离子电池富有潜力的正极材料.然而,由于不可逆的结构变化和缓慢的界面动力学,传统的多晶富锂层状氧化物正极材料循环和倍率性能较差.本文提出了一种聚乙烯基吡咯烷酮(PVP-K30)辅助共沉淀制备单晶Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)纳米片的方法.这种方法操作简单、成本低且便于放大生产.所制备的单晶纳米片内部晶格连续且无晶界,缩短了Li+的嵌入/脱嵌路径,加快了电极反应动力学过程.单晶结构还能抑制层状相向尖晶石相的不可逆相变和颗粒内部裂纹的形成,起到稳定层状结构的作用.电化学测试结果表明,所制备的Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)单晶纳米片在0.1 C倍率下的可逆容量为254.5 mA h g^(-1),在5 C高倍率下循环1000次后容量保持率为71.9%.这种简单的制备纳米片单晶材料的方法为提高富锂层状氧化物正极材料的循环性能和倍率性能提供了新的思路.
基金supported by Guangdong Major Project of Basic and Applied Basic Research(2021B0301030002)the Key R&D Program of Guangdong Province(2020B010189001,2019B010931001,2018B010109009,and 2018B030327001)+5 种基金Science and Technology Program of Guangzhou(2019050001)the National Natural Science Foundation of China(52025023,52102043,51991342,52021006,and 11888101)Beijing Natural Science Foundation(JQ19004)Guangdong Provincial Science Fund for Distinguished Young Scholars(2020B1515020043)the Pearl River Talent Recruitment Program of Guangdong Province(2019ZT08C321)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB33000000)。
文摘Consisting of one to a few atomic layers,two-dimensional(2D)materials have atomically perfect surfaces that are free of dangling bonds and exhibit various exotic physical and chemical properties.Even more exciting,one can construct new materials by stacking different 2D layers as they are generally bonded by van der Waals interactions.Therefore,in the past decade,2D materials have attracted much interest in the field of materials science,physics,chemistry and electrical/optical engineering.To implement the most anticipated applications of the 2D materials-based devices in the future,the growth of large-scale 2D single crystals is a prerequisite.Only single crystals can ensure the ultimate intrinsic performance of the materials and the uniformity of the devices.
文摘单晶Si,Si C,α-Al2O3,Li Ta O3等是制作半导体晶圆的常用功能材料,晶圆的精密加工多采用工件自旋转平面磨削(RISG)。RISG不同于传统的往复平面磨削,相互接触的砂轮和晶圆绕各自轴线旋转,依靠砂轮的轴向进给磨削。本文介绍了RISG加工的原理及磨粒运动的数学模型,分析了磨纹密度、倾斜角、系统刚度等因素对RISG加工晶圆的平面度和表面粗糙度的影响,并通过分析磨削力探索RISG的材料去除机理,展望了晶圆加工的研究方向。
