3D cross-linking N-doped graphene framework for high sulfur nanocrystal storage

Abstract

Three-dimensional (3D) nitrogen-doped graphene frameworks contributing to high-efficiency and high-stability Li-S batteries have received wide interest in energy storage fields. Herein, a 3D nitrogen-doped graphene composite framework was prepared with spatial dendritic triamines as crosslinking interconnectors, and subsequently employed for Li-S batteries with high efficiency and stability. The nanoscale spatial network of triamine-bonded graphene as molecular spacers can enlarge the interlayer spacing and change surface topography, which allows the nanocomposites to inhibit phase separation and thus capture and homogeneously store well-dispersed sulfur nanocrystals at a high capacity exceeding 70%, even by a solution process. In our work, the composite of S@GO-TAPA as the cathode material delivers the highest initial discharge capacity of 965 mAh g −1 . Besides that, an average coulombic efficiency of 91% is achieved after more than 100 cycles and 66.5% of the capacity remains, even after 100 cycles at 0.2 °C. The results suggest that the shuttle effect is remarkably suppressed. Therefore, the design strategy for cathode media is promising for fully solutionprocessing energy storage devices with printing, coating and spraying techniques.

The effect of different poly fibers separator-modified materials on blocking polysulfides for high performance Li-S batteries

“…It should be noted that three nitrogen doping forms (pyrrolic N, pyridinic N, and Quaternary N) are retained even at a carbonization temperature of 800 °C. Therefore, N components are chemically stable, which can produce more polar sites to immobilize polysulfide Frontiers in Chemistry frontiersin.org intermediates in carbon papers (Qian et al, 2019). Figure 3C displayed N 1s peaks in PPTA-KOH-G.…”