The booming development of consumer electronics and electrical vehicles urgently requires high energy density rechargeable batteries. Lithium metal is one of the most promising anodes owing to its lowest reduction potential (-3.0 V vs standard hydrogen electrode) and high theoretical specific capacity (3860 mAh/g).
The application of lithium anode is, however, still hindered by its unsatisfactory cycling stability and serious safety problems due to the growth of lithium dendrites and the continuous side reactions between lithium metal and electrolyte. It is, therefore, highly demanded to construct the 3D framework of metallic lithium anode for excellent cyclic stability achieved at a high current density as the large specific surface area can effectively reduce the practical current density and further facilitate smooth Li depositing morphology.
The research group headed by Prof. Xianfeng Li from Dalian Institute of Chemical Physics propose a novel upright structure of Li metal anode to creatively make planar Li metal stand up and realize inner growth of Li dendrites, which achieved longer cycle life of lithium metal batteries.
The upright Li anodes were well-designed and synthesized with a simple coiling method, which possessed broader reaction interface, larger Li storage space, and more durable Li+ transport than traditional planar Li anodes.
The lithium deposition of upright Li will prior to occur on upper surface. During cycling, thickened solid electrolyte interphase (SEI) would passivate the upper surface and convert dendrites growing direction from topside to inside, which effectively alleviated the lithium volume expansion and avoid short circuit caused by dendrites.
High electrolyte uptake inside of upright Li is the key to support sufficient Li+ transport/ supplement, sustaining the superior cyclic stability of Li metal anode, without sacrifice on the energy density. It exhibited superior cycling stability at a high current density of 5 mA/cm2. Further suppressing upper surface reaction and facilitating the inner surface reaction of upright Li, this unique structure can completely convert the direction of dendrites growth and greatly improve the safety and stability of lithium metal batteries.