Hard Carbons Derived from Phenyl Hyper-Crosslinked Polymers for Lithium-Ion Batteries

Abstract

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.