NiM (Sb, Sn)/N-doped hollow carbon tube as high-rate and high-capacity anode for lithium-ion batteries

Alloy-type materials are regarded as prospective anode replacements for lithium-ion batteries (LIBs) owing to their attractive theoretical capacity. However, the drastic volume expansion leads to structural collapse and pulverization, resulting in rapid capacity decay during cycling. Here, a simple and scalable approach to prepare NiM (M: Sb, Sn)/nitrogen-doped hollow carbon tubes (NiM–C) via template and substitution reactions is proposed. The nanosized NiM particles are uniformly anchored in the robust hollow N-doped carbon tubes via Ni–N–C coordination bonds, which not only provides a buffer for volume expansion but also avoids agglomerating of the reactive material and ensures the integrity of the conductive network and structural framework during lithiation/delithiation. As a result, NiSb–C and NiSn–C exhibit high reversible capacities (1259 and 1342 mAh/g after 100 cycles at 0.1 A/g) and fascinating rate performance (627 and 721 mAh/g at 2 A/g), respectively, when employed as anodes of LIBs. The electrochemical kinetic analysis reveals that the dominant lithium storage behavior of NiM–C electrodes varies from capacitive contribution to diffusion contribution during the cycling corresponding to the activation of the electrode exposing more NiM sites. Meanwhile, M (Sb, Sn) is gradually transformed into stable NiM during the de-lithium process, making the NiM–C structure more stable and reversible in the electrochemical reaction. This work brings a novel thought to construct high-performance alloy-based anode materials.