Three-dimensionally ordered macro/mesoporous TiO2 matrix to immobilize sulfur for high performance lithium/sulfur batteries

3D Net-like GO-d-Ti3C2Tx MXene Aerogels with Catalysis/Adsorption Dual Effects for High-Performance Lithium-Sulfur Batteries

High theoretical specific capacity and rich resources in nature make sulfur an ideal cathode material for lithium-metal batteries. However, the shuttle effect and sluggish reduction reaction kinetics of lithium polysulfides (LiPSs) seriously affect the performance of the batteries. Here, we report GO-d-Ti₃C₂T_x MXene aerogels with a novel three-dimensional (3D) reticular structure that served as sulfur host cathode materials for lithium-sulfur batteries (LiSBs), which benefits adsorption/catalytic conversion of LiPSs simultaneously. The dissolved LiPSs can be rapidly captured through chemisorption and then catalyzed into insoluble Li₂S by low-coordinated-state Ti on the d-Ti₃C₂T_x MXene surface. The combination of adsorption and catalysis enormously improves the capacity and cycling performance of LiSBs. At an S mass loading of 1.5 mg cm^-2, the cell with the S@GM0.4 composite electrode achieves excellent cycling performance. The discharge specific capacity of 1039 mA h g^-1 (1.56 mA h cm^-2) decays to 542.9 mA h g^-1 after 1000 cycles with a capacity fading rate of 0.048% per cycle at 0.5 C. Even at an S mass loading of 4.88 mg cm^-2, an areal capacity of 4.3 mA h cm^-2 can be achieved at 0.2 C.

Advanced Battery Materials Research at Nazarbayev University: Review

With the rapid development of new and advanced technologies, the request for energy storage device with better electrochemical characteristics is increasing as well. Therefore, the search and development for more novel and efficient energy storage components are imperative. In Kazakhstan there are several groups that were established to conduct research in the field of energy storage devices. One of them is professor Mansurov’s research group with we have a long time fruitful collaboration. Group at Nazarbayev University do research in design and investigation of advanced energy storage materials for high performance energy storage devices, including lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, and aqueous rechargeable batteries, employing strategies as nanostructuring, nano/micro combination, hybridization, pore-structure control, configuration design, 3D printing, surface modification, and composition optimization. This manuscript reviews research on advanced battery materials, provided by Nazarbayev University scientists since the last 10 years.

Three-Dimensionally Ordered Macro/Mesoporous Nb2O5/Nb4N5 Heterostructure as Sulfur Host for High-Performance Lithium/Sulfur Batteries

The severe shuttle effect of soluble polysulfides hinders the development of lithium–sulfur batteries. Herein, we develop a three-dimensionally ordered macro/mesoporous (3DOM) Nb₂O₅/Nb₄N₅ heterostructure, which combines the strong adsorption of Nb₂O₅ and remarkable catalysis effect of Nb₄N₅ by the promotion “adsorption-transformation” mechanism in sulfur reaction. Furthermore, the high electrocatalytic activity of Nb₄N₅ facilitates ion/mass transfer during the charge/discharge process. As a result, cells with the S-Nb₂O₅/Nb₄N₅ electrode delivered outstanding cycling stability and higher discharge capacity than its counterparts. Our work demonstrates a new routine for the multifunctional sulfur host design, which offers great potential for commercial high-performance lithium–sulfur batteries.

Three-Dimensionally Ordered Macroporous ZnO Framework as Dual-Functional Sulfur Host for High-Efficiency Lithium-Sulfur Batteries

A three-dimensionally ordered macroporous ZnO (3DOM ZnO) framework was synthesized by a template method to serve as a sulfur host for lithium-sulfur batteries. The unique 3DOM structure along with an increased active surface area promotes faster and better electrolyte penetration accelerating ion/mass transfer. Moreover, ZnO as a polar metal oxide has a strong adsorption capacity for polysulfides, which makes the 3DOM ZnO framework an ideal immobilization agent and catalyst to inhibit the polysulfides shuttle effect and promote the redox reactions kinetics. As a result of the stated advantages, the S/3DOM ZnO composite delivered a high initial capacity of 1110 mAh g^-1 and maintained a capacity of 991 mAh g^-1 after 100 cycles at 0.2 C as a cathode in a lithium-sulfur battery. Even at a high C-rate of 3 C, the S/3DOM ZnO composite still provided a high capacity of 651 mAh g^-1, as well as a high areal capacity (4.47 mAh cm^-2) under high loading (5 mg cm^-2).

TiO2 and Co Nanoparticle-Decorated Carbon Polyhedra as Efficient Sulfur Host for High-Performance Lithium-Sulfur Batteries

Metal organic frameworks (MOFs)-derived porous carbon is proposed as a promising candidate to develop novel, tailorable structures as polysulfides immobilizers for lithium-sulfur batteries because of their high-efficiency electron conductive networks, open ion channels, and abundant central ions that can store a large amount of sulfur and trap the easily soluble polysulfides. However, most central ions in MOFs-derived carbon framework are encapsulated in the carbon matrix so that their exposures as active sites to adsorb polysulfides are limited. To resolve this issue, highly dispersed TiO₂ nanoparticles are anchored into the cobalt-containing carbon polyhedras that are converted from ZIF-67. Such a type of TiO₂ and Co nanoparticles-decorated carbon polyhedras (CCo/TiO₂ ) provide more exposed active sites and much stronger chemical trapping for polysulfides, hence improving the sulfur utilization and enhancing reaction kinetics of sulfur-containing cathode simultaneously. The sulfur-containing carbon polyhedras decorated with TiO₂ nanoparticles (S@CCo/TiO₂ ) show a significantly improved cycling stability and rate capability, and deliver a discharge capacity of 32.9% higher than that of TiO₂ -free S@CCo cathode at 837.5 mA g^-1 after 200 cycles.