Hard carbon (7440-44-0) is a carbonaceous anode material for Li-ion and Na-ion batteries. The building units of hard carbons are random orientated hexagonal carbon layers. The stacking of such building units induces the formation of a large number of pores in the hard carbon, enabling enhanced ion storage capabilities. The mechanism of ion storage involves intercalation, adsorption, and pore filing through ion cluster formation, delivering superior electrochemical performance. Compared to conventional graphite anodes, hard carbon offers higher capacity, outstanding rate capability, excellent cycling stability, and reliable low-temperature performance, making it an ideal candidate for next-generation energy storage solutions.
A study of operando wide-angle neutron scatter (WANS) has revealed the expansion of graphene layers in hard carbon during the Na-ion insertion. The structural disorder in hard carbon predominantly occurred in the slope region and became saturated in the plateau region, providing valuable insights into the material's storage mechanism and long-term performance.