Smart hybrids of Zn2GeO4 nanoparticles and ultrathin g-C3N4 layers (Zn2GeO4/g-C3N4 hybrids) are realized by a facile solution approach, where g-C3N4 layers act as an effective substrate for the nucleation and subsequent in situ growth of Zn2GeO4 nanoparticles. A synergistic effect is demonstrated on the two building blocks of Zn2GeO4/g-C3N4 hybrids for lithium storage: Zn2GeO4 nanoparticles contribute high capacity and serve as spacers to isolate the ultrathin g-C3N4 layers from restacking, resulting in expanded interlayer and exposed vacancies with doubly bonded nitrogen for extra Li-ion storage and diffusion pathway; 2D g-C3N4 layers, in turn, minimize the strain of particles expansion and prevent the formation of unstable solid electrolyte interphase, leading to highly reversible lithium storage. Benefiting from the remarkable synergy, the Zn2GeO4/g-C3N4 hybrids exhibit highly reversible capacity of 1370 mA h g(-1) at 200 mA g(-1) after 140 cycles and excellent rate capability of 950 mA h g(-1) at 2000 mA g(-1). The synergistic effect originating from the hybrids brings out excellent electrochemical performance, and thus casts new light on the development of high-energy and high-power anode materials.