Self-Supported CoP Nanorod Arrays Grafted on Stainless Steel as an Advanced Integrated Anode for Stable and Long-Life Lithium-Ion Batteries

Abstract

To alleviate the capacity degradation of anode materials for Li-ion batteries, caused by serious volume expansion and particle aggregation, intensive attention has been devoted to the rational design and fabrication of novel anode architectures. Herein, self-supported CoP nanorod arrays have been facilely synthesized using hydrothemally deposited Co(CO₃ )_0.5 (OH)⋅0.11 H₂ O nanorod arrays as the precursor, through a gas-phase phosphidation method. As the anode for Li-ion batteries, such 3D interconnected CoP nanorod arrays show an initial discharge capacity of 1067 mAh g^-1 and a high reversible charge capacity of 737 mAh g^-1 at 0.4 Ag^-1 . After 400 cycles, their specific capacity can reach 510 mAh g^-1 ; even after 900 cycles, they can still deliver a specific capacity of 390 mAh g^-1 . CoP//LiCoO₂ full-cells also exhibit a high reversible capacity of 400 mAh g^-1 after 50 cycles. These unique 3D interconnected CoP nanorod arrays also show ultrastable cycling performance over 500 cycles when used as the anode in a Na-ion battery.

Keywords: CoP anode; Li-ion batteries; Na-ion batteries; electrochemistry; full-cells; self-supported film.