Preparation and sodium storage performance of sulfur doped pitch based carbon microspheres
Sulfur doped pitch based carbon microspheres were prepared by low-temperature and high-pressure sulfurization and car-bonization using coal direct liquefied pitch as the carbon source.The effects of carbonization temperature on the microscopic morpholo-gy,structure and electrochemical properties of sulfur doped pitch based carbon microspheres were investigated.The results show that the resulting pitch based carbon has a large number of microspheres with abundant sulfur content,and the sulfur content of the pitch based carbon obtained from carbonization at600℃is as high as8.48%(atomic percent).With the increase of carbonization temperature,the sulfur content of the pitch based carbon gradually decreases,and both the specific surface area and layer spacing gradually increases,the specific surface area increases to 301.79 m2/g,and the interlayer spacing is 0.3731 nm.The pitch based carbon obtained at 700℃has the best sodium storage performance.The specific capacity reaches 435.5 mAh·g-1 at a current density of 25 mA·g-1 with the first coulombic efficiency of 64.46%.When the current density is 0.5 A·g-1,a reversible specific capacity of the pitch based carbon is still 209.2 mAh·g-1 after 1 000 cycles.The excellent sodium storage performance is attributed to its high sulfur content,large layer spacing,and suitable pore structure.
Pitchcarbon microspheressulfur dopingsodium ion batteriesanode materials
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