Biotemplated Fabrication of Sn@C Anode Materials Based on the Unique Metal Biosorption Behavior of Microalgae

Biotemplating is an effective strategy to obtain morphology-controllable materials with structural specificity, complexity, and corresponding unique functions. Different from traditional biotemplating strategies replicating the morphology and using biogenic elements of biomaterials (e.g., C, Si, N, Fe, P, S), we take advantage of the unique heavy-metal-ion biosorption behavior of microalgae to fabricate tin-decorated carbon (Sn@C) anode materials for lithium-ion batteries. Microalgae Spirulina platensis is used as the biotemplate, the renewable carbon source, and the biosorbent. After a facile one-step heat treatment, Sn@C with tin particles (20-30 nm) dispersing into the porous carbon matrix can be obtained. Fourier transform infrared spectra reveal that metal-ion biosorption results from the complexation reactions between Sn4+ ions and the hydroxyl groups associated with alginate. The Sn@C anode shows a discharge capacity of 520 mAh g(-1) after 100 cycles, as well as excellent cycle stability and high coulombic efficiency (approximately 100%), exhibiting fascinating electrochemical performance. This facile, green, and economical strategy not only will extend the scope of biotemplating synthesis of functional materials but also will provide reference for environmental protection and water purification.