The performance of lithium ion batteries (LIBs) is highly dependent on the properties of the anode materials. Developing new carbon materials and metal oxides/sulfides with high capacities has attracted growing attention due to the limited theoretical capacity of commercial graphite. Pyrite (FeS₂) is environmental benign, inexpensive and has a high theoretical capacity of 894 mAh g⁻¹ because of its four-electron reduction by lithium, which make it promising for use as an anode material of LIBs. To improve the electrical conductivity and volume change of pyrite, hybrids made of pyrite confined in nitrogen-doped carbon nanotubes (FeS₂/N-CNTs) were fabricated by floating catalyst chemical vapor deposition (FCCVD), followed by sulfidation. Results indicate that the original Fe/N-CNTs formed during the FCCVD have iron nanowires or nanorods inside the N-CNTs and their sulfidation with sulfur vapor at 400 °C for 1, 2 and 5 h leads to FeS₂/N-CNTs with pyrite contents of 22.4, 45.2, and 55.8 wt%, respectively. The pyrite in FeS₂/N-CNTs is in two forms, one is FeS₂ nanowires confined in half-open N-CNTs and the other is FeS₂ nanoparticles attached to the outer walls of the N-CNTs as a result of diffusion out of the inner tubes. A large number of defects on the N-CNTs tube walls is necessary for the diffusion of sulfur vapor into the tubes to make the iron species accessible to the sulfur. The FeS₂/N-CNTs-45.2 wt% has the highest discharge capacity (996 mAh g⁻¹ at 0.1 A g⁻¹), good rate capability and stable cycling performance as an anode material for LIBs.

锂离子电池（LIB）的性能高度依赖于负极材料的性能。由于商业石墨的理论容量有限，开发具有高容量的新型碳材料和金属氧化物/硫化物已引起越来越多的关注。黄铁矿（FeS ₂）对环境无害，便宜，并且由于其通过锂的四电子还原而具有894 mAh g ^-1的高理论容量，这使其有望用作LIB的负极材料。为了改善黄铁矿的电导率和体积变化，限制在氮掺杂碳纳米管（FeS ₂（N-CNT）是通过浮式催化剂化学气相沉积（FCCVD），然后进行硫化制备的。结果表明，在FCCVD期间形成的原始Fe / N-CNT在N-CNT内具有铁纳米线或纳米棒，并且在400°C下用硫蒸气硫化1、2和5 h会导致FeS ₂ / N-CNTs黄铁矿含量分别为22.4、45.2和55.8 wt％。FeS ₂ / N-CNT中的黄铁矿有两种形式，一种是限制在半开放N-CNT中的FeS ₂纳米线，另一种是FeS ₂由于扩散出内管，纳米颗粒附着在N-CNT的外壁上。N-CNTs管壁上的大量缺陷对于硫蒸气向管中的扩散是必不可少的，以使铁物质易于接触硫。所述的FeS ₂ /N-CNTs-45.2重量％具有最高的放电容量（毫安996克^-1 0.1 A G ^-1），良好的倍率性能和稳定的循环性能，作为LIBS阳极材料。