Layer-by-layer (LbL) assembly is a widely used tool for engineering materials and coatings. In this Perspective, dedicated to the memory of ACS Nano associate editor Prof. Dr. Helmuth Möhwald, we discuss the developments and applications that are to come in LbL assembly, focusing on coatings, bulk materials, membranes, nanocomposites, and delivery vehicles.

Nitrogen-doped hierarchical porous carbon nanospheres (NHPCNs) with mesoscale and microscale pores are reported herein for their application in high-performance supercapacitor electrode materials (SCMs). The NHPCNs were facilely prepared via the carbonization of mesoporous polydopamine nanospheres (MPNSs) fabricated by one-step self-polymerization of dopamine using Pluronic F127 as a soft template. The influence of polymerization and carbonation temperatures on the morphologies, structures, and capacitor performances of the as-prepared NHPCNs was investigated systematically. The specific surface area of the NHPCNs can be achieved as high as 1725 m² g⁻¹, together with a pore volume of 1.85 cm³ g⁻¹. Due to their unique structure, the NHPCNs can act as high-performance SCMs and exhibit high charge storage capacity with a high specific capacitance of 433 F g⁻¹ in 6 M KOH at a current density of 0.5 A g⁻¹ and excellent stability with 95.7% of the initial capacitance after 10 000 cycles.