Tailoring neodymium-based nanostructures for high-performance supercapacitors: insights into phase evolution and carbon integration
摘要
The pursuit of efficient energy storage solutions has spotlighted rare-earth materials for their potential in supercapacitor applications. This study investigates neodymium hydroxide (Nd(OH)3), neodymium oxide (Nd2O3), and their carbon composites (Nd(OH)3@C) as electrode materials, synthesized through a hydrothermal approach followed by calcination at 500–800 °C. Structural characterization using X-ray diffraction (XRD) revealed a complete phase transformation from hexagonal Nd(OH)3 to Nd2O3 at 800 °C. Scanning electron microscopy (SEM) revealed distinct morphological evolution: pristine Nd(OH)3 exhibited rod-like structures, which became coarser upon calcination, while the carbon composites developed spherical particles that converted into hierarchical porous networks after carbon decomposition. BET analysis showed a significant increase in surface area from 14.3 m2 g−1 (pristine) to 126.2 m2 g−1 (Nd(OH)3@C-800), accompanied by enhanced porosity. Fourier Transform Infrared (FTIR) spectroscopy confirmed dehydroxylation and carbon removal during calcination. Electrochemical testing demonstrated that Nd(OH)3@C-800 achieved the best performance, delivering 198.07 F g−1 at 1 A g−1, 75% retention at 4 A g−1, and an energy density of 9.90 Wh kg−1, along with a reduced charge-transfer resistance (1810 Ω vs. 4419 Ω in pristine). These results establish clear structure–property relationships, showing that controlled calcination and carbon templating effectively transform low-surface-area hydroxides into high-performance porous electrodes for next-generation supercapacitors.