Host Materials For Lithium-sulfur Batteries Research Articles

Ordered SnO nanoparticles in MWCNT as a functional host material for high-rate lithium-sulfur battery cathode

Lithium-sulfur battery has become one of the most promising candidates for next generation batteries, and it is still restricted due to the low sulfur conductivity, large volume expansion and severe polysulfide shuttling. Herein, we present a novel hybrid electrode with a ternary nanomaterial based on sulfur-impregnated multiwalled carbon nanotubes filled with ordered tin-monoxide nanoparticles (MWCNT-SnO/S). Using a dry plasma reduction method, a mechanically robust material is prepared as a cathode host material for lithium-sulfur batteries. The MWCNT-SnO/S electrode exhibits high conductivity, good ability to capture polysulfides, and small volume change during a repeated charge–discharge process. In situ transmission electron microscopy and ultraviolet–visible absorption results indicate that the MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution into the electrolyte. Furthermore, the ordered SnO nanoparticles in the MWCNTs facilitate fast ion/electron transfer during the redox reactions by acting as connective links between the walls of the MWCNTs. The MWCNT-SnO/S cathode with a high sulfur content of 70 wt.% exhibits an initial discharge capacity of 1,682.4 mAh·g–1 at 167.5 mA·g–1 (0.1 C rate) and retains a capacity of 530.1 mAh·g–1 at 0.5 C after 1,000 cycles with nearly 100% Coulombic efficiency. Furthermore, the electrode exhibits the high capacity even at a high current rate of 20 C.

Nitrogen-doped porous carbon plates derived from fallen camellia flower for electrochemical energy storage

Nitrogen-doped porous carbon plates have been prepared by simple and cost-effective pyrolysis carbonization of an easily available biomass-fallen camellia flower and followed by alkali activation. As-prepared nitrogen-doped porous carbon (aNPCP3) possesses a high specific surface area of 2318 m2 g−1 and abundant micro/meso-pores. As a result, the aNPCP3 samples have been demonstrated to be electrodes for supercapacitors, displaying a high specific capacitance of 354 F g−1 at a current density of 0.2 A g−1 and excellent cycling stability. Further, the aNPCP3 samples used as sulfur host materials for lithium-sulfur batteries exhibit a high capacity of 1210 mAh g−1 and good cycling stability with a small capacity decay of about 0.1 % per cycle. Interestingly, it is found that their electrochemical performances are dependent on their specific surface area, pore structure, and heteroatom-doping content and type of carbon materials to a large extent. Cheapness, convenient resource, and good performance make these electrode materials displaying huge potential in cost-effective high-performance energy storage devices.