Surface Modification of Lithium Battery Anodes with Multi-Functional Block Copolymers

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Lithium metal anode is regarded as one of the most promising next generation anode materials due to its exceptional capacity and lowest electrochemical potential. Nevertheless, formation and excessive growth of lithium dendrites cause series of adverse consequences. It can penetrate the separator to cause serious safety risks and induce formation of dead lithium to harm the coulombic efficiency. Drastic volume changes tend to destroy the solid electrolyte interface layer to deteriorate cyclic stability. These drawbacks seriously hinder practical applications of the lithium metal battery. It is proposed to use multi-functional PDMS based block copolymers and their organic/inorganic nanohybrids to modify the surface of the lithium metal anodes. The PDMS based block copolymers are featured with multiple advantages such as good elastomeric property, excellent lithium affinity, outstanding chemical inertness, capable of structure modification, and good solution processing capability. They can also form nanoscale structures on the lithium metal surface via a microphase separation process. The structure and property of the lithium metal interface is modified, where the formation and growth of lithium dendrites are suppressed, and structure stability of the solid electrolyte interface layer is enhanced. With this strategy, the electrochemical performance of the lithium metal anode is effectively improved. Through this joint project, the surface modification and device performance studies are combined with advanced ex situ and in situ scattering techniques (x-ray and neutron). The methods to perform reliable surface modification of the lithium metal anodes with the multi-functional block copolymers will be established. A good control over the structure and property of the surface modified lithium metal anode interface will be achieved. The structure-performance correlation of the surface modified lithium metal anode will be unveiled, and the mechanism will be understood. The implementation of the proposal will build solid scientific ground for practical application of the lithium metal batteries.