Simultaneous enhancement of initial Coulombic efficiency and cycling performance of silicon-based anode materials for lithium-ion batteries

Abstract

Regarded as one of the most prospective anode materials for lithium-ion batteries (LIBs), silicon (Si) exhibits the highest theoretical capacity (4200 mAh g−1) among various anode materials while generally suffers from huge volume change, resultant rapid capacity fading and low initial Coulombic efficiency (ICE). Here, the ICE and cycling performance of Si-based anode have been simultaneously improved through preparing Si@C@Graphite materials where the conformal carbon modifiers derived from natural biopolymer binders covalently attached to Si particles could enhance the cycling stability, among which GA-derived carbon layer with N, O heteroatoms could best ameliorate the Li+ transport kinetics and thereby rendering superior electrochemical properties, while artificial graphite (AGr) could significantly promote the overall ICE and more effectively elevate the reversible capacity. An excellent ICE (86.4%), a prominent rate performance (1240.6 mAh g−1at 2000 mA g−1) and a promoted cycling stability (1320.5 mAh g−1at 800 mA g−1after 100 cycles) could be presented by Si@GAC@AGr anode. This research provides an effective strategy of simultaneously improving ICE and cycling performance of Si-based anodes and inspires rational design ofhigh-energy–density LIB anodes.