Halloysite Nanotube-Supported Ni/Ni-Silicate@C Anodes for High-Rate Lithium-Ion Batteries: A Clay Mineral-Based Functional Material.

Nickel silicate, a widely studied transition metal silicate, has emerged as a promising anode material for next-generation lithium-ion batteries (LIBs) owing to its high theoretical capacity, cost-effectiveness, and environmental benignity. Silicate minerals have attracted extensive attention in many fields due to their unique natural structures, superior biocompatibility, abundant reserves, and low cost. Thus, it is potential to use silicate minerals as raw materials to synthesize nickel silicates. Herein, three electrode materials (Ni-silicate/HNTs/NC, Ni-silicate/Sep/NC, and Ni-silicate/Kaolin/NC) based on three natural minerals (halloysite nanotubes, sepiolite, and kaolin) with different morphologies were synthesized and evaluated as anodes of lithium-ion batteries. For further improving the electrochemical performance and cycling stability of Ni-silicate/HNTs/NC, Ni/Ni-silicate/NC@C-2 was obtained by carbon coating and metallic nickel modification. Benefiting from the unique one-dimensional structure, high electron/lithium-ion conductivity, and abundant active sites, the obtained Ni/Ni-silicate/NC@C-2 revealed outstanding electrochemical performance (691.7 mAh g-1 at 0.5 A g-1 after 500 cycles) and excellent rate capability (545.7 mAh g-1 at 2 A g-1). Moreover, the Ni/Ni-silicate/HNTs/NC@C-2//LiFePO4 full cell presents superior rate and cycling performance with a practical application demonstration. This work provides a potential electrode material, Ni/Ni-silicate/HNTs/NC@C-2, as an anode in the future battery field and emphasizes the important role of natural minerals with unique morphology in constructing functional materials.