Network Carbon with Macropores from Apple Pomace for Stable and High Areal Capacity of Sodium Storage

Areal capacity is of importance for the wide applications of sodium-ion battery. In this work, a 3D network biowaste carbon with macropores derived from common biowaste in the form of apple pomace collected from concentrated juice factory is employed for sodium ion battery anodes. The 3D network carbon constructed with lots of shell-like macropores approximately 500 nm, and a small amount of tiny pores around 50 nm is achieved at an optimized condition. The 3D network carbon electrodes with a high mass loading of 5.1 mg cm^-2 exhibit the promising areal capacity of 1.91 mAh cm^-2 after 200 cycles. The average reversible Coulombic efficiency is 99.3%. While the gravimetric capacity retention is over 90% (208 mAh g^-1) after 200 cycles compared with a normal mass loading of 0.9 mg cm^-2. The performances show one of the best storages in the chart among ever reported areal capacity. This mainly because that the 3D network carbon structure can provide reaction microspaces, high electrical conductivity, and relieve the volumetric expansion.