Lithium metal is a promising candidate for the promotion of the next generation high energy density batteries. The employment of ultrathin Li metal anode with controllable thickness could enable a higher efficiency of Li utilization. Herein, a simple method to fabricate free-standing 10 μm ultrathin Li metal anode is developed in this work.
Although much progress has been achieved in stabilizing the Li metal anode, the current Li electrode still lacks efficiency and safety. Moreover, a practical Li metal battery requires a thickness-controllable Li electrode to maximally balance the energy density and stability.
Lithium metal anodes are among the most promising candidates for further increasing the energy density of lithium ion batteries and all-solid-state batteries. A reduction of the anode thickness by using ultrathin lithium metal films is a crucial requirement to achieve a significant overall reduction of thickness on cell level.
This work proposes the use of vacuum thermal evaporation of Li metal to produce ultra-thin, dense, homogeneous, smooth, and high-performance Li metal anodes. It is demonstrated that the thermally evaporated ultra-thin Li metal anode has a passivation layer which is one order of magnitude thinner compared to that of commercial extruded Li metal.
The larger the area of an ultra-thin battery, the smaller its internal resistance. The biggest feature of ultra-thin lithium polymer batteries is that the thickness of the entire battery is less than 1mm, which is as thin as paper and has a long cycle life and low self-power consumption.
As a result, the ultrathin Li composite anode exhibits a superior lifespan expanded to 2000 cycles in a symmetric cell, as well as a better capacity and rate capability than that of bare Li anode in full cell, fulfilling the requirements of high energy density and stable cycling life.