Gas phase self-assembly of carbon confined Fe1-xS nanoparticles/exfoliated graphite composite with nano-/micro-structure for long-life anode of potassium-ion batteries

Rechargeable potassium-ion batteries (KIBs) show great potentials in the applications of large-scale electrochemical energy storage to substitute the analogue of lithium-ion batteries. However, the effective anode materials of KIBs with long cycling lifespan and satisfactory rate performance are still required to be exploited urgently. In this study, a facile and scalable two-step gas phase strategy has been developed to construct a carbon coated Fe1-xS/exfoliated graphite (C@Fe1-xS/EG) nano-/micro-hybridized structure with low-cost ferrocene and EG as the raw materials. After the featured gas phase self-assembly process, ultrafine Fe1-xS nanoparticles covered by a thin carbon coating with quasi-graphitic texture are found to be firmly anchored on the surface of EG. Meanwhile, the multiscale pore structure and moderate specific surface area are well maintained. Benefitting from the favorable synergistic effect created by the rational association between C@Fe1-xS NPs and the EG matrix, the C@Fe1-xS/EG composite exhibits substantially enhanced electrochemical performances, such as high reversible capacity of 347 mAh g(-1) at 0.14 A g(-1), enduring cycling ability up to 2000 cycles and greatly improved rate capability. The excellent electrochemical stability is attributed to the co-protection of EG matrix and carbon coating that prevents the pulverization of Fe1-xS and maintains the integrity of electrode structure. The kinetics analyses indicate that the accelerated K+/e(-) transportation rate and high surface pseudocapacitive contribution result in the elevated rate performance. This study demonstrates the promising application prospect of EG-based electrode materials for high-performance KIBs. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study developed a novel two-step gas phase strategy to construct a carbon coated Fe1-xS/exfoliated graphite hybrid structure, aiming to enhance the electrochemical performance of rechargeable potassium-ion batteries.