Nitrogen-doped carbon nanotube-buffered FeSe2 anodes for fast-charging and high-capacity lithium storage

• Natural hematite is employed as the raw material to synthesize FeSe 2 @N-CNT. • This synthesis method is readily available and highly scalable. • 2. The FeSe 2 @N-CNT anode shows ultrafast rate capability to 20 A g −1 . • 3. Long-term cycle stability (953 mAh g −1 after 1500 cycles at 10 A g −1 ) is achieved. Fast−charging and high−capacity have become indispensable requirements for next−generation energy storage systems. However, large−scale fabrication of high−capacity anode materials for fast Li + storage remains a huge challenge. Herein, natural hematite is employed as the starting material to achieve scalable synthesis of nitrogen−doped carbon nanotube−buffered FeSe 2 (FeSe 2 @N−CNT) through a facile catalyzing & selenizing process. The readily−available raw materials and simple processing procedures are suitable to industrial−level batch production. In this FeSe 2 @N−CNT composite, the FeSe 2 particles are efficiently encapsulated into the interwoven carbon nanotube network, which can enlarge the contact area with electrolyte, enhance the electrical conductivity, shorten the Li + /e – diffusion length and buffer the drastic volume variation of FeSe 2 during lithiation/delithiation. As an anode material of lithium ion batteries (LIBs), the FeSe 2 @N−CNT electrode delivers a significantly high specific capacity of 806 mAh g −1 at a high current density of 20 A g −1 (relative to 915 mAh g −1 at 0.1 A g −1 ). More importantly, long−term cycle stability (953 mAh g −1 after 1500 cycles at 10 A g −1 ) is achieved, which outperforms most FeSe 2 −based Li + storage anodes reported so far. The easy−to−implement mass production and the high Li + storage property enable FeSe 2 @N−CNT as a promising candidate as a commercial anode for LIBs.