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），尤其是在温和的水解中的系统，是因为Zn阳极和电解质的大量成本，环境良性和情人级别的毒性，因此是最重要的。 5855 mAh/cm3，由于多个电子转移金属离子和相对高密度，MNO2材料是由于合适的隧道或相对的，因此与LI阳极（2061 mAh/cm3）相比层次结构和丰度，环境友好和大的工作电压窗口，例如有限的插入通道空间o溶解和验证电荷/放电的沉积，未兑现的机制介入）和MNO2阴极的低电子电导率尚未得到解决。该博士学位的Zn2+ L利用率的大直径。 ENT诱发的晶状金属阳离子将稳定晶格空间，并研究其他阴离子 - 将通过液体去角质化的艰难效应利用来提供工程策略。能量和结构稳定性。 ，能量，能量和稳定性，电化学反应和离子 - 扩散动力学。对于超薄材料的形态演变（图1中的先前工作），阴极材料的填料密度将与Electrical Ltd合作在KTP Associates的支持下，研究了阴极材料的可能的质量生产路线，并开发了用于大规模储能设备的原型。