In Situ Synthesis of Amorphous GeSe/CNT Composite via Defective-carbon-mediated Chemical Bonding for Ultrastable Na Ion Storage.

Herein, we report the in-situ synthesis of amorphous GeSe/CNT composite via defective-carbon-mediated chemical bonding for ultrastable Na-ion storage. Structural defects in CNTs play a crucial role in the chemical bonding and bonding strength in GeSe/CNTs composites. Specifically, the bonding strength tends to increase with increasing defect concentrations of CNTs. Remarkably, the strong chemical bonding between GeSe and CNTs significantly weakens Ge-Se bonds and promotes amorphization of GeSe, thus facilitating a reversible conversion reaction and enhancing Na-ion diffusion. Consequently, GeSe/CNTs composite exhibits outstanding cyclability of 87.9% even after 1000 cycles at 1 A g-1 and a high-rate capability of 288.3 mA h g-1 at 10 A g-1 . Our work presents a promising approach for the amorphization of electrode materials enabled by the defective-carbon-mediated strong chemical bonding for Li-, Na-, and K-ion batteries.