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The practical applications of lithium-sulfur (Li S) batteries remains remote because of low utilization of sulfur and short cycle life caused by low conductivity of sulfur, shuttle effect of lithium polysulfides and severe volume expansion. It is therefore exigent to rationally design an effective sulfur host. Here a novel sulfur host material--alpha molybdenum trioxide (α-MoO3) spheres are introduced into Li S battery cathode acting as lithium polysulfides absorbent and efficient matric of sulfur. The abundant oxygen atoms on the surface of α-MoO3, making it form chemical binding interactions with lithium polysulfides, which can effectively alleviate the dissolution of lithium polysulfides. Moreover, α-MoO3 as the matric of sulfur alleviates volume expansion of active sulfur and enhanced the utilization of sulfur, which results in improving the battery performances. As a result, S/α-MoO3 electrode with the sulfur content of 68 wt.% shows an initial discharge capacity of 1086.2 mAh g−1 and good capacity retention is obtained with 912.8 mAh g−1 after 400 cycles at 0.5 C. After 50 cycles at rates ranging from 0.1 to 2 C, the cell still returns a high specific capacity of 916.5 mAh g−1 at 0.5 C. The results demonstrate α-MoO3 was a promising sulfur host material for promoting the performances of Li S batteries with high sulfur content cathode.

Hollow TiO2/Sb/C spheres that nano Sb embedded into the interlayer between inner hollow TiO2 sphere and outer carbon layer, were designed, synthesized and investigated. The physical properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical performances were acquired by discharge/charge cycles, rate cycles, cyclic voltammograms (CVs) and electrochemical impedance spectra (EIS). The results indicated that nano Sb embedded did not decline the cycle stability and rate property of TiO2/C anode, but its reversible capacity was increased by a large margin. Li+ diffusion coefficient of TiO2/Sb/C-2 and TiO2/Sb/C-1 reached to 4.76 × 10−16 cm2 s−1 and 4.10 × 10−16 cm2 s−1, while the value of TiO2/C was 2.46 × 10−16 cm2 s−1. At 1000 mA g−1, initial reversible capacity for TiO2/Sb/C-2 reached to 230.6 mAh g−1, and its capacity loss per cycle was only 0.0201% from 2nd to 1200th cycle. This work provided a conception to manufacture high capacity TiO2-based anodes for lithium ion battery.

Spinel LiMn2O4 was introduced into cathode for lithium‑sulfur (Li-S) batteries due to its stable structure, low price, good lithium ion conductivity and much active sites of Mn atoms which could capture polysulfides. Ultraviolet/visible absorption, Fourier transform infrared and X-ray photoelectron spectroscopies verified strong adsorption of Li2S6 by LiMn2O4. It could be explained by following possible adsorption mechanism that part Mn4 + on the surface of LiMn2O4 was reduced and transformed Mn3 + and Mn2 +, at the same time, some S62 − was oxidized and transformed Li2S6 − x (1

Lithium-sulfur (Li-S) batteries attract much attention due to its high specific capacity and energy density compared to lithium-ion batteries (LiBs). Herein, a novel composite named as (void/nano-Li 4 Ti 5 O 12 pieces)@C [(v/n-L)@C] was designed and prepared as a sulfur host. Spinel Li 4 Ti 5 O 12 here as a multifunctional additive played as polysulfide adsorbent agent and fast Li + conductor, and carbon shell was designed as electronic conductor, as well as volume barrier to limit the volume expansion caused by sulfur. As-prepared (S/nano-Li 4 Ti 5 O 12 pieces)@C [(S/n-L)@C] are core-shell spheres, which are about 200 nm in size. Nano-Li 4 Ti 5 O 12 and sulfur were coated by the outer carbon shell with a thickness of about 20 nm. The experimental results show that electrochemical performances of (S/n-L)@C cathode were enhanced effectively compared to S@C cathode. At 0.5C and 1C, the discharge capacity of (S/n-L)@C was 33.5% and 40.1% higher than that of S@C at 500 th cycle. Even at 2C, its capacity reached 600.9 mAh g −1 at 1000 th cycle. Li + conductivity of (S/n-L)@C was one order of magnitude higher than that of S@C, which was reach to 2.55 × 10 −8 S cm −1 . The experiment results indicate Li 4 Ti 5 O 12 plays a promotional role on electrochemical performances of sulfur cathode, especially for stable cycling performance and high rate performance.

Tetragonal FeSbO 4 with a coating carbon layer of ∼20 nm (FeSbO 4 /C) was synthesized via simple solid state method. The physical properties were investigated by X-ray diffraction (XRD), thermogravimetric (TG), scanning electron microscopy (SEM) and transmission microscopy (TEM). The electrochemical characteristics were studied via cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and galvanostatic charge/discharge. Compared to FeSbO 4 , electronic conductivity of FeSbO 4 /C was obviously increased by coating a thin carbon layer. Furthermore, its reversible capacity and cycle performance were also improved. At 50 mA g −1 , the capacity of FeSbO 4 /C reached to 201.1 mAh g −1 at 200th cycle, while the value of FeSbO 4 was 107.2 mAh g −1 . The results indicate that FeSbO 4 /C is a potential anode material for lithium ion batteries.

Nano-Sn confined to matrixes for fabricating high capacity and long cycle life anodes has attracted extensive attention in recent years, but using Li+ conductor as structure stabilizer to construct matrixes have not been studied yet. Sn-based anodes using spinel Li4Ti5O12 as Li+ conductor and structure stabilizer can prolong the cycle life of electrodes, which is due to “zero strain” property and high Li+ conductivity coefficient of Li4Ti5O12. Herein, spherical (nano-Sn/Li4Ti5O12)@C was designed, synthesized and investigated, which was labeled as (n-Sn/L)@C. Nano-Sn and nano-Li4Ti5O12 pieces were mixed uniformly in inner carbon shell, where some vacuum space was beneficial for Sn expanding/shrinking during Li+ insertion/extraction. Moreover, Li+ diffusion coefficient of (n-Sn/L)@C-1 and (n-Sn/L)@C-2 was high as 6.09 × 10−8 and 9.47 × 10−9 cm2 s−1, whereas the value of Sn@C was 7.54 × 10−10 cm2 s−1. The charge capacity (corresponding to the reversible capacity on full cell) loss of per cycle of (n-Sn/L)@C-1 and (n-Sn/L)@C-2 from 1st to 350th cycle was only 0.081% and 0.094% at 500 mA g−1, while the value of Sn@C was 0.160%. The enhanced electrochemical performances of (n-Sn/L)@C benefited from intimate contact of nano-Li4Ti5O12 and nano-Sn within the carbon shell, and high Li+ conductivity of Li4Ti5O12.

Nowadays, energy storage systems have been considered as an effective way to meet the urgent demand for portable electronic products and electric vehicle industry, which requires the development of power sources that can provide high capacity as well as high safety, resulting in an increase on secondary batteries with excellent performances and non-pollution. Lithium-sulfur (Li-S) battery is considered as one of the most promising candidate batteries due to its high theoretical energy density, low cost and non-toxicity. Despite many advantages associated with Li–S battery, it is hard to be applied to commercial-scale production owing to its shuttle effect, insulating nature, agglomeration of sulfur, polysulfide dissolution and fast capacity decay during charge–discharge process. To meet these challenges, numerous characteristics of sulfur electrode have been designed, such as sufficient space to accommodate sulfur volume expansion, small dimensions of active material to avoid pulverization, and appropriate electrolyte additives to minimize the shuttle effect. According to previous studies, morphology of sulfur carriers has an important effect on electrochemical performances of Li–S battery. This review mainly aims at present status of different morphological sulfur carriers including carbon, metallic oxide, organic polymer and their composites, then summarizes their advantages, unresolved problems and common synthesis methods, respectively. At last, development and future prospects of Li–S battery are also presented.

VPO4 is introduced into the lithium sulfur battery system acting as efficient matrix for sulfur and absorbent for polysulfides. Adsorption experiments reveal that VPO4 has good adsorbability for polysulfides, which also has been demonstrated by ultraviolet/visible absorption spectrum. Fourier transform infrared spectroscopy further indicates that there exists chemical interaction between VPO4 and polysulfides. X-ray photoelectron spectroscopy study provided in-depth detailed analysis of chemical interaction. Furthermore, VPO4 as a matrix of sulfur which can alleviate volume expansion of sulfur and increase the utilization of active sulfur. The cell with the S/(VPO4 + CNTs) electrode exhibits 1056.0 mAh g−1 and 651.2 mAh g−1 at 0.5 C during the first and 500th cycles, which is much higher than 792.0 mAh g−1 and 486.5 mAh g−1 of the S/(AB+CNTs) electrode. Even at 2 C, the discharge capacity of the S/(VPO4 + CNTs) electrode shows 566.8 mAh g−1 after 800 cycles. These results demonstrate that VPO4 as efficient matrix for sulfur and absorbent for polysulfides is beneficial for improving electrochemical performances of lithium-sulfur battery.