Porous carbons derived from microalgae with enhanced electrochemical performance for lithium-ion batteries

Graphical abstract: Carbon materials derive from microalgae possess well-formed mesoporors structure, and appear orderly graphitic microcrystalline. Therefore, the product exhibits low irreversible capacity and capacity loss, delivers a high capacity of 355 mA h g⁻¹ under 1C rate even after 500 cycles, and maintains high retention above 95%. - Highlights: • Porous carbons derived from microalgae are prepared through a simple, efficient and economical pyrolysis process. • The orderly graphitic microcrystalline provide the excellent electronic conductivity and substantial reversible capacity. • The good electrochemical performance is attributed to hierarchical porous structure and microcrystalline graphitic carbon. • Porous carbons deliver high capacity of 445 mA h g⁻¹ at 0.1 C, excellent capacity retention 95% after 500 cycles under 1 C. - Abstract: Porous carbons derived from microalgae were prepared using a pyrolysis method. The microstructure and electrochemical performance were studied using X-ray diffraction, Raman spectrometer, scanning and electron microscopy techniques. The electrochemical performance was investigated using electrochemical methods. A carbon sample pyrolyzed at 900 °C exhibited a hierarchical pore structure with a large amount of microcrystalline graphitic domains. As a result, this sample delivered the best electrochemical performance with specific charge capacities of 445 mAh g⁻¹ at 0.1 C and 370 mA h g⁻¹ at 1 C, respectively. In addition, this sample showed a capacity retention of 95% after 500 cycles at 1 C. The good electrochemical performance of the pyrolytic carbon is attributed to the combined contributions of the hierarchical porous structure and microcrystalline graphitic carbon domains.