Charge‐Discharge Characteristics of Mesophase‐Pitch‐Based Carbon Fibers for Lithium Cells

Abstract

Mesophase‐pitch‐based carbon fibers were heat‐treated at high temperatures (2600 or 2800°C) and examined as anodes for lithium secondary batteries. Four types of carbon fibers were used whose cross‐sectional views are: a radial texture with wedge (type A), a radial texture with fine zigzag layers (type B), a double texture (type C), and a concentric texture (type D). Lithium could not be deintercalated after the first lithium intercalation in the type A carbon fiber. The structure of the type A fiber was destroyed during lithium intercalation. The other three types of carbon fibers showed good rechargeability on the first cycle, but demonstrated different behavior after 30 cycles. The highest lithium intercalation and deintercalation capacity was observed for the radially oriented carbon fiber (type B). The x‐ray results showed a reversible change in the lattice along the c‐axis during the intercalation and deintercalation cycle.