锂硫电池用无枝晶生长的金属锂负极

The lithium-sulfur batteries consisting of lithium anode and sulfur cathode afford a very high theoretical energy density of 2600 Wh/kg, which is 3-5 times higher than that of routine lithium ion batteries. Due to the poor cycling performance of lithium-sulfur batteries mainly attributed by the metal anode, the solid electrolyte interphases (SEI) of lithium anode in a lithium-sulfur cell are strongly considered. In this proposal, dendrite-free Li metal anodes are investigated for lithium-sulfur batteries. The SEI interlinked with the Li metal is probed by the high resolution transmission electron microscopy and in-situ microscopy-electrochemical workstation. The composite of SEI on the Li anode is determined by the electron energy loss spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The evolution of SEI is tracked and the couple between diffusion of lithium ions and electrochemical deposition of lithium is discerned. Based on the new insights into the SEI and related principles on the transport phenomena and reaction engineering, the structure of SEI is modulated through the introduction of the second element in the lithium anode, the surface structure of lithium metal, the rational design of electrolyte, as well as the strategy for cell operation. These work provides the material and chemical engineering foundation of lithium metal anodes for high capacity, high stability, and high safety lithium-sulfur batteries for sustainable energy storage.

金属锂作为负极，硫作为正极构成的锂硫电池具有常规锂离子电池3-5倍的理论能量密度，是有望满足电动汽车及个人电子设备所需的下一代储能系统。申请人针对锂硫电池遇到金属锂负极枝晶生长带来的安全性低、稳定性差的问题，提出锂硫电池中锂的固体电解质界面膜调控的思路。本项目以锂硫电池作为研究体系，负极锂的固体电解质界面膜（SEI）作为研究对象，开展SEI结构及调控的研究。通过在线原位和离线高分辨表征剖析锂硫电池中金属锂的SEI结构，探索锂硫电池中金属锂的SEI调控原理，获得‘锂离子扩散-电化学反应’耦合原理，并发展金属锂的化学组成、表面结构、电解质、金属锂保护剂以及充放电方式的调控手段，以望获得锂硫电池用无枝晶生长的高安全高稳定金属负极的材料化工基础。

金属锂作为负极，硫作为正极构成的锂硫电池具有2600 Wh/kg理论能量密度，是有望满足电动汽车及个人电子设备所需的下一代储能系统。申请人针对锂硫电池遇到金属锂负极枝晶生长带来的安全性低、稳定性差的问题，提出锂硫电池中锂的固体电解质界面膜调控的思路。本项目以锂硫电池作为研究体系，负极锂的固体电解质界面膜（SEI）作为研究对象，开展了SEI结构及调控的研究。通过在线原位和离线高分辨表征剖析锂硫电池中金属锂的SEI结构，探索了锂硫电池中金属锂的SEI调控原理，获得‘锂离子扩散-电化学反应’耦合原理，并发展了金属锂的化学组成、表面结构、电解质、金属锂保护剂以及充放电方式的调控手段。