Coal tar pitch (CTP) has become an ideal choice in the preparation of anode precursors for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) because of its abundant carbon content, competitive pricing and adjustable structure properties. In this paper, sulfurized pitch-based carbon (SPC-800) was obtained by allowing CTP to react with sulfur at 350 °C and subsequently achieve carbonization at 800 °C. SPC-800 was more disordered and had a larger layer spacing than carbonized CTP (PC-800). Upon utilization as an anode for LIBs, SPC-800 possessed a higher reversible specific capacity (478.1 mAh g⁻¹ at 0.1 A g⁻¹), while utilization in SIBs displayed a capacity of 220.9 mAh g⁻¹ at 20 mA g⁻¹. This work is an important guide to the design of high-performance anodes suitable for use with both LIBs and SIBs.

Hyper-crosslinked polymers are attracting extensive attention owing to their ease of design and synthesis. Based on the flexibility of its molecular design, a hyper-crosslinked polymer with a π-conjugated structure and its derived carbon were synthesized by the Friedel–Crafts reaction. The polymer and its derived hard carbon material were characterized by FTIR, ¹³C NMR, Raman, BET, and other characterization tools. The electrochemical properties of both materials as anode electrodes of lithium-ion batteries were investigated. Benefiting from the highly cross-linked skeleton and conjugated structure, the as-prepared carbon materials still had high specific surface area (583 m² g⁻¹) and porosity (0.378 cm³ g⁻¹) values. The hard carbon (CHCPB) anode possessed the powerful reversible capacity of 699 mAh g⁻¹ at 0.1A g⁻¹, and it had an excellent rate of performance of 165 mAh g⁻¹ at the large current density of 5.0 A g⁻¹. Long-cycle performance for 2000 charge/discharge cycles displayed that the capacity was kept at 148 mAh g⁻¹ under 2 A g⁻¹. This work contributes to a better understanding of the properties of hard carbon materials derived from hyper-crosslinked polymers and how this class of materials can be further exploited in various applications.

FDO’s wide boiling range and complex composition hinder controlled synthesis of high-performance mesophase pitch. Here, FDO was separated into light, middle, and heavy narrow fractions by vacuum distillation. Multi-scale characterization traced molecular evolution and mesophase development. The light fraction consists of three-ring aromatics with short alkyl side chains and shows the lowest reactivity, yielding limited condensation and poor stacking with isotropic regions and dispersed spheres. The middle fraction contains four-ring aromatics with moderately extended chains, exhibiting enhanced reactivity and undergoing nucleation, growth, coalescence, and disintegration of mesophase spheres. However, insufficient volatiles restrict shear orientation, forming a mosaic texture. The heavy fraction has four-ring aromatics with the longest alkyl chains and the lowest substitution degree, giving the highest reactivity. During thermal cracking, long chains release abundant radicals and volatiles; directional escape generates shear, promoting rapid growth and ordered alignment of aromatic lamellae. At 440 °C for 12 h, this fraction yields high-quality mesophase pitch with small-domain texture, a low softening point (295 °C), and high anisotropic content (98.8%). The pitch shows excellent spinnability, and derived carbon fibers (tensile strength ~1.45 GPa, modulus ~151 GPa) outperform a commercial reference processed under identical conditions. This study reveals molecular-level regulation of mesophase evolution by narrow fraction structures.