Effective Carbon Pores to Improve the Electrochemical Performance of Phosphorus as an Anode for Sodium Ion Batteries

• Published in: ACS applied energy materials 2021-12, Vol.4 (12), p.13841-13846
• Main Authors: Komine, Yuki, Urita, Koki, Notohara, Hiroo, Moriguchi, Isamu
• Format: Article
• Language: English
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.1c02605

We propose here that carbon pores provide key reaction sites for stable electrochemical reactions in phosphorus sodium ion batteries (SIBs). Phosphorus showing a high theoretical capacity (2596 mA h/g) due to a three-electron reaction with sodium ions is a remarkable negative material for SIBs. However, both low electrical conductivity of phosphorus and the capacity fading due to a large volume change during the charge–discharge process lead to a low reaction efficiency. The phosphorus introduced into relatively large mesoporous or macroporous carbons showed a high capacity of 2445 mA h/g at the first charge process, whereas capacities are no more than 1100 mA h/g in microporous or small mesoporous carbons in which the cyclability is also poor. This result clearly indicates that the carbon pores with a pore size close to or above 50 nm are effective reaction spaces for stabilization of the alloying–dealloying reaction of phosphorus with sodium ions.