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Cu Substitution Stabilizes Oxygen Redox in High Na Content P3‐Type Na0.75Li0.2Cu0.05Mn0.75O2 Cathode with Unexpected High Energy Density

Year: 2024

Type: article

Abstract: Oxygen redox enhances the specific energy of sodium cathodes, but the other performance remains unsatisfactory. By introducing Cu into P2 lattice to replace Li cations, P3‐type Na0.75Li0.2Cu0.05Mn0.75O2 with high Na concentration is achieved. This modification induces notable alteration in the lattice structure, specifically increasing the interplanar spacing of NaO6 from 3.6 Å to 3.8 Å. The resultant P3‐type cathode delivers a remarkable capacity of 253 ± 1.3 mAh g−1 with energy density of 680 mWh g−1, setting a benchmark for P3‐type sodium cathodes. The high capacity can be attributed to the activation of Mn3+/ Mn4+ redox pair following Cu substitution. Further investigations confirm that Mn3+/ Mn4+, Cu2+/ Cu3+ and O2−/On− redox pairs all contribute to the high performance. The absence of O vacancy and the reduction in phase transitions enhance the cyclic performance with capacity retention of 86.3% at 0.5C. Additionally, the small diffusion energy barrier (34.6 KJ mol−1) results in a high Na diffusion coefficient (1.332 × 10−9 cm2 s−1), thereby promoting superior rate behavior with a capacity of 200.8± 2.1 mAh g−1 at 5C. These results demonstrate the advantages of the P3‐type Na0.75Li0.2Cu0.05Mn0.75O2 cathode over the other Na cathodes, suggesting high potential for application in high‐energy storage fields.

Source: Advanced Functional Materials

DOI: 10.1002/adfm.202411561

Authors: Yan Li, Duojie Wu, Jiening Zheng, Meng Gu, Chengkang Chang

Institutions: Shanghai Institute of Technology, Shanghai Jiao Tong University, Eastern Institute of Technology, Ningbo, Southern University of Science and Technology

Language: English

Topic: Advancements in Battery Materials

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: bronze

Funders: National Natural Science Foundation of China, Shanghai Institute of Technology, Development and Reform Commission of Shenzhen Municipality, Southern University of Science and Technology