A simple composite protective layer coating that enhances the cycling stability of lithium metal batteries

• Published in: Journal of power sources 2015-06, Vol.284, p.103-108
• Main Authors: Lee, Hongkyung, Lee, Dong Jin, Kim, Yun-Jung, Park, Jung-Ki, Kim, Hee-Tak
• Format: Article
• Language: English
• Subjects: Composite protective layer; High current density; Lithium ion battery; Lithium metal; Lithium plating
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2015.03.004

Metallic lithium is the most promising negative electrode for high-energy rechargeable batteries due to its extremely high specific capacity and its extremely low redox potential. However, the low cycle efficiency and lithium dendrite formation during the charge/discharge processes consistently hinder its practical application. In this report, we present a stabilized Li electrode on which a Li+ ion conductive inorganic/organic composite protective layer (CPL) is coated. With the introduction of the CPL, the Li dendrite growth and electrolyte decomposition are effectively suppressed; consequently, stable Li plating/stripping at high current densities up to 10 mA cm−2 is possible. Nanoindentation tests demonstrate that the shear modulus of the CPL at narrow indentations is 1.8 times higher than that of the Li metal, which provides a theoretical understanding for its efficacy. Moreover, the LiCoO2/Li cell incorporating CPL exhibits excellent cycling stability up to 400 cycles at 1 mA cm−2 (1 C-rate), which demonstrates practical applicability in Li ion batteries through replacing the graphite anode with a CPL-coated Li metal anode. •Composite protective layer (CPL) was introduced in Li metal-based batteries (LMB).•Stable Li plating/stripping at high current density (10 mA cm−2) became possible.•The CPL is capable of mechanically suppressing of Li dendrite formation.•The shear modulus of the CPL is nearly 2 times larger than that of Li.•Enhanced cycle performance of LiCoO2/Li cell with the CPL at 1 mA cm−2 (400 cycles).