Sodium-ion batteries are promising next-generation electrical-energy-storage devices due to the relative low cost, and the natural abundance of sodium resources. Yet developmental anodes in sodium-ion batteries such as carbonaceous materials have adagio sodium ion diffusion kinetics, huge volume expansion, poor rate performance and cycle stability. Herein, we report a high-performance sodium ion storage anode material, i.e., a unique nanonetwork-structured carbon (NNSC) with a valuable hollow nanosphere as network unit by developing a facile, efficient and post-treatment-free strategy. The as-constructed NNSC exhibits a three-dimensional interconnected hierarchical porous network and a luxuriant accessible surface area, which greatly enhance sodium ion transport and storage. Thus, the obtained NNSC demonstrates excellent sodium ion storage performance, including a high capacity of 250 mA h g(-1), good rate capability, and ultra-long-term cycle life up to 9000 cycles. Such attractive capabilities could accelerate the application of sodium-ion batteries in large-scale energy storage. (C) 2019 Elsevier Inc. All rights reserved.