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

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 pi-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, C-13 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 m(2) g(-1)) and porosity (0.378 cm(3) 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.