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(CO 3 ) 0.5 (OH) ⋅ 0.11 H 2 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//LiCoO 2 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.