Apple-Biowaste-Derived Hard Carbon as a Powerful Anode Material for Na-Ion Batteries

Modern industrial agriculture is strongly influenced by product norms and standards, resulting in massive amounts of fresh fruit that is left in the field or wasted in spite of their good nutritional value. Herein, we present the synthesis of hard carbon from natural apple biowaste, and its use of biomass is a suitable strategy for the development of cheap and powerful carbon-based active materials for Na-ion batteries. The hard carbon exhibits a good rate capability [112mAhg(-1) at 5C (1Ag(-1))], excellent long-term cycling stability (1000 cycles at 5C), and high specific capacity (245mAhg(-1) at 0.1C) with full retention after 80 cycles. The full capacity (250mAhg(-1)) of the hard carbon is also obtained in Na-ion cells by using the layered P2-type NaxNi0.22Co0.11Mn0.66O2 cathode. The good electrochemical performance as well as the low cost and environmental friendliness of the apple-biowaste-derived hard carbon proves its suitability for future Na-ion batteries.