Metal nanodots anchored on carbon nanotubes prepared by a facile solid-state redox strategy for superior lithium storage

Alloying-based electrode materials (e.g. Si, Sn, Sb, Bi, etc.) are the promising anode candidates for next-generation lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) owing to their high specific capacities, but they suffer from huge volume changes upon lithium/sodium insertion/extraction processes. On the other hand, such alloying anodes usually require a complicated and high energy-consumption synthesis process (e.g. Si anode by a magnesiothermic reduction at over [Formula: see text]C, Sn, Sb and Bi anodes by a high-temperature carbothermic reduction at 600–[Formula: see text]C), thus limiting their practical application for replacing low-cost graphite. In this work, we develop a straightforward solid-state strategy for a general synthesis of metal nanodots (Sn, Sb and Bi) supported on carbon nanotubes (CNTs) by using the reduction potential differences of metal salts and NaBH 4 as the reaction power at room temperature. Owing to the very mild reaction, the resulted active component is small enough (2–5[Formula: see text]nm) with diffusion-less and nucleation-less barriers upon alloying/dealloying reaction, thus enabling high electrode stability and high capacity retention. Taking Sn anode as an example, the obtained Sn/CNTs deliver a high reversible capacity of 415[Formula: see text]mAh g[Formula: see text] at 0.5[Formula: see text]A g[Formula: see text] after 1000 cycles without obvious capacity decay. Such findings indicate that the proposed solid-state synthetic method could offer a great potential for realizing large-scale and economic applications of energy storage materials.