Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE...Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE),continuous Na loss during long-term operation,and low sodium-content of cathode materials.In this scenario,presodiation strategy by introducing an external sodium reservoir has been rationally proposed,which could supplement additional sodium ions into the system and thereby markedly improve both the cycling performance and energy density of SIBs.In this review,the significance of presodiation is initially introduced,followed by comprehensive interpretation on technological properties,underlying principles,and associated approaches,as well as our perspectives on present inferiorities and future research directions.Overall,this contribution outlines a distinct pathway towards the presodiation methodology,of significance but still in its nascent phase,which may inspire the targeted guidelines to explore new chemistry in this field.展开更多
水系锌离子电池(ZIBs)以其低成本、高安全性和环境友好的优点受到了研究者的广泛关注,成为大规模电化学储能系统的理想选择之一。然而锌金属负极在应用时面临着锌枝晶生长、腐蚀反应和副反应等难以克服的障碍,严重制约了水系锌离子电池...水系锌离子电池(ZIBs)以其低成本、高安全性和环境友好的优点受到了研究者的广泛关注,成为大规模电化学储能系统的理想选择之一。然而锌金属负极在应用时面临着锌枝晶生长、腐蚀反应和副反应等难以克服的障碍,严重制约了水系锌离子电池的发展。探索可替代锌金属的储锌负极是应对上述问题的有效策略,因此研究者围绕过渡金属氧化物、硫化物和导电聚合物开展了深入研究。以TiX_(2)(X=S,Se)为代表的二维过渡金属硫族化合物(TMDs)具有较大的层间距和快速的离子传输通道,可作为锌离子电池的负极,但其储锌反应机制尚未得到完整的揭示。在本文中,我们使用密度泛函理论(DFT)计算方法系统地研究锌离子在TiX_(2)中的嵌入反应。首先我们采用群论去描述嵌锌TiX_(2)的稳定层间构型的特点,定义了一个依赖于超胞并且只涉及平移旋转两种对称操作的群,其子群可以用来描述层间构型的对称性,而且用来描述最稳定构型的子群总是倾向于有最大的阶数。基于该计算得到的一系列对应于不同放电深度的TiX_(2)的稳定结构,我们发现TiS_(2)和TiSe_(2)两种材料在锌嵌入/脱出过程中的开路电压(OCV)均低于0.5V。态密度(DOS)的计算结果表明TiX_(2)具有很好的电子导电性,而分波态密度(PDOS)的结果显示随着锌的嵌入闭壳层的Ti^(4+)还原成开壳层的Ti^(3+),并且伴随着Zn―X键的生成。Bader电荷分析的结果表明随着X的嵌入,X相比Ti得到了更多的负电荷,意味着X也参与了TiX_(2)的氧化还原过程。爬坡弹性带方法(CINEB)计算的结果证实了Zn^(2+)在TiX_(2)中具有较低的扩散能垒(对于TiS_(2)是0.333 e V,对于TiSe_(2)是0.338e V)。本文的研究结果不仅从本质上证明了TiX_(2)适合作为锌离子电池的嵌锌负极材料,而且为其他高性能TMDs电池材料的DFT研究提供了新的见解。展开更多
基金the financial support from the National Nature Science Foundation of China(No.U20A20249)the National Key Research and Development Program of China(2021YFB3800300)the Shenzhen Science and Technology Innovation Commission(KCXST20221021111216037)。
文摘Sodium-ion batteries(SIBs)are expected to offer affordability and high energy density for large-scale energy storage system.However,the commercial application of SIBs is hurdled by low initial coulombic efficiency(ICE),continuous Na loss during long-term operation,and low sodium-content of cathode materials.In this scenario,presodiation strategy by introducing an external sodium reservoir has been rationally proposed,which could supplement additional sodium ions into the system and thereby markedly improve both the cycling performance and energy density of SIBs.In this review,the significance of presodiation is initially introduced,followed by comprehensive interpretation on technological properties,underlying principles,and associated approaches,as well as our perspectives on present inferiorities and future research directions.Overall,this contribution outlines a distinct pathway towards the presodiation methodology,of significance but still in its nascent phase,which may inspire the targeted guidelines to explore new chemistry in this field.
文摘水系锌离子电池(ZIBs)以其低成本、高安全性和环境友好的优点受到了研究者的广泛关注,成为大规模电化学储能系统的理想选择之一。然而锌金属负极在应用时面临着锌枝晶生长、腐蚀反应和副反应等难以克服的障碍,严重制约了水系锌离子电池的发展。探索可替代锌金属的储锌负极是应对上述问题的有效策略,因此研究者围绕过渡金属氧化物、硫化物和导电聚合物开展了深入研究。以TiX_(2)(X=S,Se)为代表的二维过渡金属硫族化合物(TMDs)具有较大的层间距和快速的离子传输通道,可作为锌离子电池的负极,但其储锌反应机制尚未得到完整的揭示。在本文中,我们使用密度泛函理论(DFT)计算方法系统地研究锌离子在TiX_(2)中的嵌入反应。首先我们采用群论去描述嵌锌TiX_(2)的稳定层间构型的特点,定义了一个依赖于超胞并且只涉及平移旋转两种对称操作的群,其子群可以用来描述层间构型的对称性,而且用来描述最稳定构型的子群总是倾向于有最大的阶数。基于该计算得到的一系列对应于不同放电深度的TiX_(2)的稳定结构,我们发现TiS_(2)和TiSe_(2)两种材料在锌嵌入/脱出过程中的开路电压(OCV)均低于0.5V。态密度(DOS)的计算结果表明TiX_(2)具有很好的电子导电性,而分波态密度(PDOS)的结果显示随着锌的嵌入闭壳层的Ti^(4+)还原成开壳层的Ti^(3+),并且伴随着Zn―X键的生成。Bader电荷分析的结果表明随着X的嵌入,X相比Ti得到了更多的负电荷,意味着X也参与了TiX_(2)的氧化还原过程。爬坡弹性带方法(CINEB)计算的结果证实了Zn^(2+)在TiX_(2)中具有较低的扩散能垒(对于TiS_(2)是0.333 e V,对于TiSe_(2)是0.338e V)。本文的研究结果不仅从本质上证明了TiX_(2)适合作为锌离子电池的嵌锌负极材料,而且为其他高性能TMDs电池材料的DFT研究提供了新的见解。
