NiP2/C nanocomposite as a high performance anode for sodium ion batteries. (20th January 2022)

• Record Type: Journal Article
• Authors: Lee, Jongwon; Kim, Kyeong-Ho; Kim, Hyung-Ho; Hong, Seong-Hyeon
• Is Part Of: Electrochimica acta. Volume 403(2022)
• Publication Date: 2022-01-20
• Subjects: Sodium ion battery -- Anode material -- Metal phosphide -- High energy mechanical milling -- Nanocomposite; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.139686
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: The NiP2 nanoparticles are synthesized via a high energy mechanical milling. The NiP2 electrode shows the conversion reaction mechanism for sodium storage. The voltage drop effect and capacity activation at early cycles are demonstrated. The NiP2 /C composite electrode showed the excellent cycle retention. Abstract: Nickel phosphide (NiP2 ) nanoparticles were prepared via a high energy mechanical milling (HEMM), and their electrochemical properties as an anode for sodium ion batteries (SIBs) were studied. As-synthesized NiP2 was highly agglomerated nanoparticles of 100∼200 nm, which were composed of ∼10 nm nanocrystallites. The NiP2 electrode showed the reversible conversion reaction by forming the Na3 P and Ni phases along with unreacted NiP2 and delivered the discharge and charge capacities of 653 and 489 mAh g − 1, respectively, with an initial Coulombic efficiency of 75% at a current density of 50 mA g − 1 . The low reaction potential between Na and NiP2 inhibited the full conversion reaction, which required an activation process. In addition, NiP2 /C nanocomposite was fabricated by HEMM using as-synthesized NiP2 and acetylene carbon black. The high resolution transmission electron microscopy (HRTEM) image indicated that the NiP2 nanoparticles were completely covered with ∼10 nm thick carbon layer. The NiP2 /C nanocomposite electrode exhibited the improved sodium storage performance and delivered a specific capacity of 428 mAh g − 1 after 100 cycles at a current density of 50 mA g -1 . The enhanced cycle performance of NiP2 /C nanocomposite was attributed to high electrical conductivity, high Na + ion mobility, and reduction of nanoparticle aggregation during cycling. Furthermore, NiP2 /C nanocomposite was successfully operated even at the full cell configuration. Graphical abstract: Image, graphical abstract