Research Update: Hard carbon with closed pores from pectin-free apple pomace waste for Na-ion batteries

Herein, we report a hard carbon derived from industrial bio-waste, i.e., pectin-free apple pomace. The structural, morphological, and electrochemical properties of the hard carbon are reported. The impact of the bio-waste on the closed porosity is discussed, providing valuable insights into the sodium storage mechanism in hard carbons. Most importantly, the hard carbon delivers good electrochemical performance, high specific capacities of 285 mAh g−1, and a very good capacity retention of 96% after 230 cycles at 0.1 C.