Nanostructural design of MnO2 cathodes for rechargeable aqueous Zn-ion batteries

可充电水系锌离子电池MnO2正极的纳米结构设计

• 批准号: 2604856
• 金额: --
• 依托单位: University of Lincoln
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2604856
• 关键词: Nanostructural; design; MnO2; cathodes; rechargeable

Zn-ion batteries (ZIBs), especially systems in mild aqueous electrolytes, are the subject of intense interest due to the abundance and relatively low cost of Zn anodes and electrolytes, environmental benignity and lower-level of toxicity. Importantly, ZIBs can be a ready-to-use technique for all battery companies as they can use the same battery fabrication facilities as LIBs.Theoretically, zinc anodes offer an ultrahigh volumetric capacity of 5855 mAh/cm3, compared to that of Li anodes (2061 mAh/cm3), due to multiple electron transfer per metal ion and relatively higher density. Moreover, Zn can be easily employed in cells without strict restrictions of air and water. Among different cathode materials, MnO2 materials are favourable due to their suitable tunnel or layered structures and the abundance, environmentally friendly nature and large working voltage window. However, problems such as limited intercalated channel space, poor stability due to dissolution and deposition of such materials during charge/discharge, unclarified mechanism (simultaneous proton intercalation and side product deposition) and low electron conductivity of MnO2 cathodes are yet to be solved. In addition, the large diameter of hydrated Zn2+ (~4.3 Å) and the high polarisation of Zn2+ inhibit the full utilisation of the structures. This PhD studentship aims at developing nanostructured MnO2 for ZIBs, and the project is divided into three stages: Stage 1) Cathode design The unstable features of MnO2 will be resolved by inducing cation and anion defects. Different pre-intercalated metal cations will be induced to expand the lattice space and stabilise the crystal structures. The cation, anion vacancy or other anion replacements will be introduced and investigated. The proposed strategies can improve electron conductivity, expand the diffusion channels of the materials. Then, two nano-engineering strategies will be provided. Ultra-thin 2D pre-intercalated MnO2 will be fabricated via a liquid exfoliation process, thus facilitating rapid diffusion and efficient structure utilisation for Zn-ion storage. Through this strategy, the tunnel structure of pre-intercalated MnO2 have the possibility to be direct hosts for Zn-ion storage without an initial conversion reaction, thus improving the pristine energy efficiency and structural stability. Another approach is to build hierarchical structures decorated with considerable nanopores via template-assisted hydrothermal synthesis and the composition with conductive carbon frameworks. The materials will be characterised by various techniques to understand the physical and chemical properties. Stage 2) Battery fabrication After successfully obtaining new materials from Stage 1, Zn-ion storage properties of materials will be evaluated to understand capacity, energy/power density, energy efficiency and stability, electrochemical reactions and ion-diffusion kinetics. The mechanism study of the battery cathode can be carried out by ex-situ and in-situ equipment in UoL Chemistry and synchrotron-based resources in Diamond Light Source, such as in-situ AFM for morphological evolution of ultra-thin materials (previous work in Figure 1). The packing density of the cathode materials will be optimised via the collaboration with One Electrical Ltd. Stage 3) Large-scale device Battery performance target will be set by GH, WA and One Electrical Ltd. The student will investigate possible mass production routes for cathode materials, and develop prototypes for large-scale energy storage devices with the support from KTP associates.

Zn-ION电池（ZIB），尤其是在轻度水解中的系统，由于锌阳极和电解质的抽象和相对低成本，环境良性和较低的毒性水平，因此引起了人们的关注。重要的是，ZIBS可以成为所有电池公司的现成技术，因为它们可以使用与LIBS相同的电池制造设施。与LI阳极相比，锌阳极的超高体积容量为5855 mAh/cm3（2061 mAh/cm3），因此，由于多型电子和相对较高的金属转移。此外，Zn可以在细胞中轻松进行，而无需严格限制空气和水。在不同的阴极材料中，MNO2材料由于其合适的隧道或分层结构以及抽象，环保性质和大型工作电压窗口而有利。但是，诸如电荷/放电过程中此类材料的溶解和沉积，未划出的机制（同时质子插入和侧产物沉积）以及MNO2阴极的电子电导率较低的问题，诸如由于插入量和沉积而导致的稳定性较差，诸如稳定性较差，MNO2阴极尚未解决诸如稳定性，MNO2阴极尚未解决，诸如稳定性，MNO2阴极的较低电子电导率等问题。另外，水合Zn2+（〜4.3Å）的大直径和Zn2+的高极化抑制了结构的全部利用。该博士生旨在为ZIBS开发纳米结构的MNO2，该项目分为三个阶段：1阶段1）阴极设计MNO2的不稳定特征将通过诱导的阳离子和阴离子缺陷来解决。将诱导不同的交换前金属阳离子扩大晶格空间并稳定晶体结构。将引入和研究阳离子，阴离子空位或其他阴离子替代品。提出的策略可以提高电子电导率，扩大材料的扩散通道。然后，将提供两种纳米工程策略。超薄的2D预裂化的MNO2将通过液体去角质过程制造，从而产生快速扩散和有效的结构利用来用于Zn-ION存储。通过这种策略，预裂化的MNO2的隧道结构可以成为Zn-ION存储的直接宿主，而无需初始转换反应，从而提高了原始能源效率和结构稳定性。另一种方法是通过模板辅助氢合成和用导电碳框架进行考虑，建立以纳米孔进行考虑的层次结构。材料将以各种技术来理解物理和化学性质的特征。第2阶段）电池制造成功从第1阶段获得新材料后，将评估Zn-ION储存特性，以了解容量，能量/功率密度，能量效率和稳定性，电化学反应和离子 - 扩散动力学。电池阴极的机理研究可以通过钻石光源中的UOL化学和基于同步加速器的资源（例如用于超薄材料的形态进化的位置AFM）中的原位和基于同步加速器的资源（图1中的先前工作）进行。阴极材料的填料密度将通过与一个电气有限公司的合作进行优化。第3阶段3）大规模设备电池性能目标将由GH，WA和一个Electrical Ltd设定。学生将研究阴极材料的质量生产路线，并为KTP Assoctectes提供支持的大型存储设备的原型。