报告题目：通过调控枝晶生长方向制备可循环充放电锂-金属电极
（Making Li-Metal Electrodes Rechargeable by Controlling the Direction of Dendrite Growth）
报 告 人：谢剑 教授
报告时间：2019年05月31日（周五）上午10:10
报告地点：郑州大学主校区化学馆208报告厅
报告人简介：
谢剑,博士,美国普渡大学印第安纳波利斯分校机械和能源工程系的教授。在天津大学获得化学工程(专业方向电化学工程)学士学位，在美国迈阿密大学获得化学博士学位。
谢剑教授长期从事聚合物燃料电池、制氢及储氢技术、锂金属电池、锂离子电池安全、大规模储能技术-液流氧化还原电池（兆瓦级）、清洁煤技术、纳米及复合材料、生物材料及装置等方面的研究；发表期刊论文55余篇，专利4项，申请专利11项，著述2章，8年内获科研资助超486万美元。
谢剑教授是美国国家自然科学基金委员会、美国能源部先进技术发展局、加拿大国家自然科学基金委的评审委员，近年来先后参与了数十个国家的自然科学基金及政府基金项目的评审工作，担任了12个国际著名期刊如自然、国际化学、能源、材料科学、电化学杂志等的评委；谢剑教授是美国电化学协会、化学协会、材料研究协会会员，也是2011年意大利国际应用能源会议的组织者及会议主持人。
报告摘要：
The long-standing issue of Li dendrite formation and growth during the repeated plating/stripping processes prevents the high specific capacity/energy Li metal from being used as the anode in practical applications for batteries. We have developed a novel and unique method to transform the low-dimensional, fiber-like structured Li into a higher-dimensional Li with a dense layer by controlling the dendrite growth direction. This was achieved by simultaneously growing Li dendrites from two opposite directions until they meet, which caused the growth along the protrusion direction to stop and restart in a perpendicular direction. After several cycles, the dendrites grew into a dense Li layer. A battery separator coated with functionalized nanocarbon (FNC) was used to realize such control. Forming such a dense Li layer effectively alleviate the SEI formation from the dendrites which in turn, greatly reduces the decomposition of electrolyte as well as the drying-out of Li metal battery cells. SEM and in situ TEM proved the working principles. The Li metal was studied for three different electrolyte systems: carbonates (LiPF6 in EC/EMC and LiClO4 in EC/PC) and ethers (LiTFSI in DOL/DME) for long term cycling, Columbic efficiency and AC impedance in a Li/LiFePO4 coin cell configuration, showing excellent cycle life (>800 cycle with 80% initial capacity), improved efficiency, and reduced solid electrolyte interphase (SEI) formation. This method not only provides a universal rechargeable Li metal anode for practical batteries (Li-metal oxides, Li-polymer, Li-Air, and Li-S), but it also opens a new avenue for solving the dendrite issues of other alkali metals such as Na and K.
