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Transition-metal sulfides (TMSs) powered by conversion and/or alloying reactions are considered to be promising anode materials for advanced lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, the limited electronic conductivity and large volume expansion severely hinder their practical application. Herein, we report a covalent coupling strategy for TMS-based anode materials using amide linkages to bind TMSs and carbon nanotubes (CNTs). In the synthesis, the thiourea acts as not only the capping agent for morphology control but also the linking agent for the covalent coupling. As a proof of concept, the covalently coupled ZnS/CNT composite (CC-ZnS/CNT) has been prepared, with ZnS nanoparticles (∼10 nm) tightly anchored on CNT bundles. The compact ZnS-CNT heterojunctions are greatly beneficial to facilitating the electron/ion transfer and ensuring structural stability. Due to the strong coupling interaction between ZnS and CNTs, the composite presents prominent pseudocapacitive behavior and highly reversible electrochemical processes, thus leading to superior long-term stability and excellent rate capability, delivering reversible capacities of 333 mAh g–1 at 2 A g–1 over 4000 cycles for LIBs and 314 mAh g–1 at 5 A g–1 after 500 cycles for SIBs. Consequently, CC-ZnS/CNT exhibits great competence for applications in LIBs and SIBs, and the covalent coupling strategy is proposed as a promising approach for designing high-performance anode materials.

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Magnesium (Mg) doped hydroxyapatite (HAP)-gelatin (GEL) one-dimensional nanofibers were prepared in the aqueous GEL solution at low temperature (38 uC). The influence of GEL and Mg on morphology and crystal structure was systematically investigated. Different amount Mg doped HAP-GEL and HAP-GEL nanofibrils doped with different amounts of Mg were obtained by self-assembly along with gelatin, and pure HAP and HAP doped with Mg were sphere nanoparticles in the absence of GEL. Fourier transform infrared (FT-IR) analysis showed that chemical bonding between calcium ions of HAP and carboxyl groups of GEL molecules led to a red shift of the 1395 cm 21 band of GEL. The incorporation of Mg ions into the composite phase caused the decrease of the lattice parameters and Ca/P molar ratio in the HAP solid samples. Differential thermal analysis and thermogravimetric analysis (DTA/TG) features and FT-IR spectra of HAPGEL composite materials were very similar to those of dentine.

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