Rapid Formation of an Artificial Polymer Cladding on a Lithium Metal Anode by In Situ Ultraviolet Curing to Regulate Lithium Ion Flux

As an ideal anode material of lithium metal for high-energy-density batteries, the development of lithium metal batteries (LMBs) has been limited by the Li dendrite's growth and accumulation of dead Li. To solve this problem, a highly elastic artificial polymer layer coated on the surface Li anode by rapid ultraviolet radical polymerization is developed. The clad poly(methyl methacrylate-acrylic acid-sulfobetaine methacrylate) (P(MMA-AA-SBMA)) terpolymer not only shows good interfacial compatibility with Li metal due to the surface formation process by in situ light solidification but also contains functional anion groups of −COO– and −SO3–, contributing the convenient channels to regulate the transport of Li ions. Ascribed from the stable interface of clad Li and the suppressed decomposition reaction of the liquid electrolyte in the later cycle stage, the Li||LiCoO2 full cell exhibits good cycle stability, maintaining 96% of initial capacity after 100 cycles in 1C rate between 3 and 4.35 V, compared with that of 67% for bare Li. Thus, the artificial polymer cladding promotes the electrochemical stability of Li metal, providing a facile way for application in high-energy-density LMBs.