Boosted Na+-MnO2 supercapacitor performance via strong metal support interaction

• Published in: Journal of colloid and interface science 2025-03, Vol.682, p.865-874
• Main Authors: Wang, Kailun, Wang, Junjie, Qian, Jun, Yu, Qijun, Bai, Jia-qi, Wei, Yuxue, Chen, Jingshuai, Wu, Mingyuan, Sun, Song, Mao, Chang-Jie
• Format: Article
• Language: English
• Subjects: Cu nanoparticles; Graphene; Metal-support interaction; MnO2; Supercapacitors
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.11.252

[Display omitted] •Na+ ions were introduced into δ-MnO2, enhancing ion migration within its layered structure.•A Cu/graphene substrate improves MnO2 conductivity and dispersion via strong metal-support interactions (SMSI).•The composite exhibits a high specific capacitance of 655 F g−1 at 1 A/g and excellent cycling stability.•An asymmetric supercapacitor with Cu/G/MnO2 achieves a specific capacitance of 75 F g−1 at 1 A g−1.•This study offers a simple method to boost MnO2-based supercapacitors using SMSI effects for improved performance. MnO2 is widely utilized as an electrode material in supercapacitors. However, overcoming challenges such as sluggish ion migration, aggregate tendency, and low conductivity is imperative for optimizing MnO2-based supercapacitors. Herein, NaMnO4 was employed as the Mn precursor to introducing a higher concentration of small Na+ ions into the layer structure of δ-MnO2. This elevated Na concentration fosters efficient ion migration within the MnO2 lattice. Moreover, Na+-MnO2 was deposited onto Cu/graphene (Cu/G) composites. Leveraging the strong metal-support interactions (SMSI) between Cu and graphene, the resulting composite demonstrates enhanced conductivity and reduced aggregation. Combining MnO2 with Cu/G resulted in a conductivity of 5.78 × 10–3 S cm−1, which is significantly better than that of MnO2. The composite material exhibits an exceptional electrochemical performance, boasting a specific capacitance of 655 F g−1 at 1 A g−1 and impressive long-term stability, retaining 95 % of its capacitance after 4000 cycles at 10 A g−1. Additionally, a 1.6 V asymmetric supercapacitor was assembled, featuring carbon as the anode, Cu/G/MnO2 as the cathode, and 1 M KOH as the electrolyte, achieving a superior specific capacitance of 75 F g−1 at 1 A g−1. Cu/G/MnO2//carbon demonstrates a maximum energy density of 27 Wh kg−1 at a power density of 0.8 W kg−1. This study underscores a facile strategy to enhance MnO2-based supercapacitors by leveraging the SMSI effect for boosted performance.