A melamine–formaldehyde resin nanosphere interlayer as a “Li+ redistributor” to stabilize Li metal anodes

Abstract

In comparison to traditional graphite anode materials, Li metal anodes are distinguished by a high theoretical specific capacity and low redox potential, making Li an optimal anode material for next-generation high-energy-density batteries. However, the intrinsic high reactivity of lithium metal can readily lead to uneven deposition of Li⁺ during the cycling process, resulting in the formation of lithium dendrites and volume expansion problems accompanied by substantial safety hazards. To protect the Li metal anode, we combine a sol–gel strategy and a simple physical bonding method to construct a novel homogeneous melamine–formaldehyde resin nanosphere (MFNS) interlayer. The experimental results demonstrate that the abundant pyrrolic N and pyridinic N functional groups present in MFNSs exhibit a strong affinity and attraction to Li⁺. During the deposition process, the MFNS interlayer redistributes the inhomogeneous Li⁺ flux, resulting in a uniform distribution of Li⁺ and guiding the homogeneous nucleation and deposition of lithium metal. Thanks to the MFNS-covered Li anodes, the assembled symmetrical cell possesses a long life of 1560 h at 1 mA cm⁻² with 1 mA h cm⁻². Consequently, this work presents a novel stabilization strategy for the development and design of Li metal anodes.