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Lithium-sulfur batteries have become one of the most promising high-energy batteries owing to their high energy density and low cost. Nevertheless, one of the major problems is the infamous shuttle effect of polysulfides, which causes active material sulfur loss and low Coulombic efficiency. Here, we designed a 3-D configuration electrodes. Multi-walled carbon nanotubes paper (MWCNTsP) was used as the current collector, and MWCNTs film was used as the interlayer (MWCNTsI) between the positive electrode and the separator. The unique configuration retarded the dissolution and dispersion of polysulfides. The electrochemical tests showed that the initial discharge capacity reached 1352 mAh/g and the Coulombic efficiency reached around 100% with the 3-D configuration electrode (MWCNTsP-S@MWCNTsI). The discharge capacity remained 1028 mAh/g after 20 cycles. Additionally, the batteries maintained a specific capacity of 902 mAh/g, 782 mAh/g and 509 mAh/g at the current rate of 1 C, 2 C and 5 C, respectively. [ABSTRACT FROM AUTHOR]

A 3-dimensional carbonized multi-walled carbon nanotube (MWCNT) paper was used as the host of nano-tin oxide (SnO2) for lithium-ion batteries (LIBs). The cellulose fibers were fully mixed with MWCNTs in water. Then, the paper was obtained via vacuum filtration. Carbonization was carried out in a vacuum furnace at 1460°C. SnO2 slurry was coated on the carbonized MWCNT paper (CMP). Scanning electron microscopy (SEM) was utilized to observe the anode electrode. The images of SEM indicated that the nano-SnO2 was embedded into the holes of the porous CMP collector. This contributed the increase of contact interface area of the nano-SnO2 and the collector and the significantly reduced interface resistance. Electrochemical tests showed that the initial discharge capacity reached 1745 mAh g−1 with a coulumbic efficiency (CE) of 70.39% at a current density of 50 mA g−1. The composite electrode still maintained a reversible capacity of 753 mAh g−1 with a CE of 98% at a current density of 200 mA g−1 after 100 cycles. These marvelous composite electrodes exhibited a promising future for the next generation of LIBs. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes have been synthesized by floating reactant method in a vertical tubular reactor. An internal short approach process was developed to achieve the pre-lithiated multiwalled carbon nanotube MWCNTs/graphite composite anodes. Lithium-ion capacitors (LICs) were composed of a pre-lithiated multiwalled carbon nanotubes/graphite composite anode and an activated carbon (AC) cathode. The electrochemical performance of LICs with different MWCNTs content was investigated through galvanostatic charge/discharge and electrochemical impedance. The results show that the charge-discharge performance of LICs was greatly improved with the addition of MWCNTs in anodes. LIC25 (25 wt% MWCNTs) was found to achieve the optimal electrochemical performance. The LIC25 hold a specific capacitance of 58.2 F/g at the current density of 100 mA/g. The maximum energy density and power density were up to 96 Wh/kg and 10.1 kW/kg, respectively, in the current range of 100~8000 mA/g. The continuous galvanostatic charge-discharge cycling tests revealed that the LIC25 maintained excellent capacity retention of 86% after 3000 cycles. [ABSTRACT FROM AUTHOR]