Synergistic Design of Cathode Region for the High-Energy-Density Li–S Batteries

Abstract

The synergistic design of cathode region was conducted to minimize the shuttle effect of polysulfides and decrease the loading of inactive components in order to acquire high-energy-density lithium-sulfur (Li-S) batteries. The well-designed cathode region presented two special characteristics: one was the intertwined nanofibers interlayer based on ultrafine TiO nanocrystal uniformly embedded within N-doping porous carbon; the other was the lightweight and three-dimensional current collector of fibrous cellulose paper coated by reduced graphene oxide. In consequence, the decent reversible capacity of 874.8 mA h g was acquired at 0.1 C with a capacity retention of 91.83% after 100 cycles. Besides, the satisfactory capacity of 670 mA h g was delivered after 300 cycles at 1 C with the small decay rate of only 0.08%. Because of higher capacity and lower loading of inactive component in cathode region, the energy density of cell increased more than five times compared with unmodified cell. Moreover, to further enhance the energy density, the high-sulfur-loading electrode was fabricated. A good areal capacity of 4.27 mA h cm was retained for the cell with the active material of 4 mg cm and the cycle stability was also well-maintained. In addition, due to the flexibility of interlayer and current collector, Li-S full cell (in pouch cell format) was easily curved. Therefore, the synergistic design for cathode region, which combines the flexible and mass-produced interlayer and current collector together, provides an effective access to Li-S batteries with high energy density and flexibility for practical application.

Sulfur Immobilizer by Nanoscale TiO2 Trapper Deposited on Hierarchical Porous Carbon and Graphene for Cathodes of Lithium–Sulfur Batteries

“…The peaks of C, O, Ti, and S elements can be easily observed in the full‐scan XPS spectrum shown in Figure S3 of the Supporting Information. The high‐resolution XPS spectrum of Ti 2p shown in Figure c presents two peaks at 464.9 and 459.3 eV, which respectively correspond to the Ti 2p 1/2 and Ti 2p 3/2 levels in the TiO bonds, indicating that the predominate state of Ti element is Ti +4 . Figure d presents the high‐resolution XPS spectrum of S 2p in the HPC@TiO 2 @S composite.…”

Recent advances on flexible electrodes for Na-ion batteries and Li–S batteries

“…Table 6 depicts the working potential range, capacity, and cycling stability of recently reported various kinds of Li-S batteries with flexible cathode materials [57, . Table 7 shows the working potential range, capacity, cycling stability, lighting LED at bent state, and cycling stability at bent state of recently reported several types of flexible Li-S batteries [57,[159][160][161][162][163][164][165][166][167][168][169][170][171][172][173][174][209][210][211] . Foldable Li-S battery can be fabricated by impregnation of the active materials into the super-elastic carbon-nanotube current-collector film in a checkerboard pattern.…”

“…Besides, Fan et al [166] have fabricated Li-S battery ( Fig. 8 b) containing rGO-cellulose fiber paper-S (reduced graphene oxide coated cellulose fiber paper-S) as cathode, Li as anode, and TiO 2 -NC -N-porous-C (TiO 2 nanocrystal embedded in N doped porous carbon) as interlayer.…”

Recent development of metal compound applications in lithium–sulphur batteries

“…[69][70][71][72][73] A TiO 2 nanowire-embedded graphene (TiO 2 NW/G) hybrid membrane was prepared by Manthiram's group. 74 In this hybrid membrane, the graphene with high conductivity was used as the current collector, while the TiO 2 NWs were used as a polysulphides shuttling inhibitor as well as the catalyst to accelerate the polysulfide reduction and oxidation.…”