三维氧化物负极的结构调控及电化学储钠应用

Sodium-ion batteries (SIBs) require increased energy and power densities before they become alternative to current lithium-ion batteries in application areas like renewable energy and smart grid. Oxides based on Sn, Sb, and Bi are appealing for SIBs, owing to their unique electrical properties and significantly higher capacities than carbonaceous anodes. The challenge with these anodes lies in the huge volume changes during the alloying reaction that leads to pulverization of the electrode and poor capacity retention as well as conventional planar electrode configuration that always trades off between available energy and the capability to release this energy. ..This project aims at mitigating these issues by engineering three-dimensional (3D) electrode architecture of these oxides. 3D electrodes are capable of maximizing power and energy density yet maintaining short ion transport lengths. 3D oxide anodes of Sn, Sb, Bi will be directly grown on metallic substrates by a deposition route, and further modified with surface modifications. Electrochemical sodium storage behaviors of 3D electrodes will be evaluated. The wisdom and reaction mechanism behind the electrochemical process will be systematically probed using various electrochemical approaches. Moreover, theoretical modeling coupled with in-situ characterziations will be conducted to illustrate the benefits of 3D architecture and surface modifications. Finally, full cells of SIBs based on 3D architecture electrodes will be designed and developed. This work would provide valuable insight into the efficient application of sodium electrode materials as well as other energy materials.

锡、锑、铋的氧化物具有独特的导电性、大容量和合金化能力，是极有潜力的钠离子电池材料。然而，常规的二维电极结构无法消除储钠过程巨大的体积变化带来的影响，同时也导致合金电极的能量与功率相互制约。本项目设计三维结构电极，在增加单位面积内的活性物质量的同时使离子扩散的路程始终保持在较短的距离，从而有望同时解决上述难题。本项目拟采用无模板法直接在基底上生长锡、锑、铋氧化物的三维有序结构，通过关键实验参数调控三维产物的化学组成和微观结构，进一步对这些三维电极进行表面修饰。采用电化学手段和谱学方法研究这些组成和结构特征对三维电极的储钠性能和反应历程的影响规律；结合理论模拟探讨材料的构效关系及三维电极的动力学优势。在此基础上，开发具有高能量和高功率的钠离子全电池，为三维电极的实际应用提供实验基础和理论依据。

锡、锑、铋的氧化物具有独特的导电性、大容量和合金化能力，是极有潜力的钠离子电池材料。然而，常规的二维电极结构无法消除储钠过程巨大的体积变化带来的影响，同时也导致合金电极的能量与功率相互制约。本项目系统开展了三维结构电极的设计、可控制备、化学修饰及电学和电化学储钠性能表征的工作。我们通过电化学阳极氧化、电化学阴极沉积和水热方法，设计了一系列具有不同的相组成、尺寸和形貌的三维结构电极。我们进一步对三维结构电极进行结构修饰，调控材料的电荷传输性能和电化学性能。我们采用电化学手段和谱学方法重点研究这些三维结构充放电的机理和动力学特性。并利用第一性原理计算和COMSOL相场模拟对三维结构的电荷传输行为进行了分析，揭示三维电极在储钠过程中的动力学优势。相关工作已经发表标注本项目资助的SCI论文30多篇，其中多篇发表在材料领域的高水平期刊如Nature Communications, National Science Review, Advanced Materials等，申请国家发明专利7项，培养博士2名，硕士8名。在项目执行期间，申请人入选教育部人才计划，获批江苏省科学基金杰出青年基金1项、江苏省高等学校自然科学研究重大项目1项。获功能材料学会“青年研究奖”和苏州市自然科学优秀学术论文二等奖。