 Spherical sponge-like carbon superstructure, NCS, assembled by 2D nanosheets is rationally and efficiently designed for K-plus storage. The optimized NCS electrode exhibits an outstanding rate capability, high reversible specific capacity, 250 mAh G-1 at 200 mA G-1 after 300 cycles, the superior performance can be attributed to the unique robust spherical structure and 3D electrical transfer network. This article was authored by Yen Huali, Kuei Xiao, Tsonghuang, and others.