Sn0.1-Li4Ti5O12/C as a promising cathode material with a large capacity and high rate performance for Mg-Li hybrid batteries

The development prospects of conventional Li-ion batteries are limited by the paucity of Li resources. Mg-Li hybrid batteries (MLIBs) combine the advantages of Li-ion batteries and magnesium batteries. Li+ can migrate rapidly in the cathode materials, and the Mg anode has the advantage of being dendrite-free. In this study, a type of Li4Ti5O12 composite material doped with Sn4+ and a conductive carbon skeleton (Li4Ti4.9Sn0.1O12/C, Sn0.1-LTO/C) was prepared by a simple one-pot sol-gel method. The doped Sn4+ replaces part of Ti4+ in the crystal lattice, which makes Ti3+ require charge compensation, thus improving the ionic conductivity. The intervention of the conductive carbon skeleton further improves the conductivity of the Sn0.1-LTO/C composite material. The performance of Sn0.1-LTO/C as the cathode of MLIBs is explored. The initial discharge capacity was 159.1 mA h g-1 at 0.5 C, and it was maintained at 105 mA h g-1 even after 500 cycles. The excellent electrochemical performance is attributed to a small amount of Sn doping and the involvement of the conductive carbon skeleton, which indicated that the Sn0.1-LTO/C composite material provides great potential application in MLIBs.

Exploring 2D Energy Storage Materials: Advances in Structure, Synthesis, Optimization Strategies, and Applications for Monovalent and Multivalent Metal-Ion Hybrid Capacitors

The design and development of advanced energy storage devices with good energy/power densities and remarkable cycle life has long been a research hotspot. Metal-ion hybrid capacitors (MHCs) are considered as emerging and highly prospective candidates deriving from the integrated merits of metal-ion batteries with high energy density and supercapacitors with excellent power output and cycling stability. The realization of high-performance MHCs needs to conquer the inevitable imbalance in reaction kinetics between anode and cathode with different energy storage mechanisms. Featured by large specific surface area, short ion diffusion distance, ameliorated in-plane charge transport kinetics, and tunable surface and/or interlayer structures, 2D nanomaterials provide a promising platform for manufacturing battery-type electrodes with improved rate capability and capacitor-type electrodes with high capacity. In this article, the fundamental science of 2D nanomaterials and MHCs is first presented in detail, and then the performance optimization strategies from electrodes and electrolytes of MHCs are summarized. Next, the most recent progress in the application of 2D nanomaterials in monovalent and multivalent MHCs is dealt with. Furthermore, the energy storage mechanism of 2D electrode materials is deeply explored by advanced characterization techniques. Finally, the opportunities and challenges of 2D nanomaterials-based MHCs are prospected.

Cotton textile inspires MoS2@reduced graphene oxide anodes towards high-rate capability or long-cycle stability sodium/lithium-ion batteries

Textile-based electrodes show superior energy storage performances, including high-rate capability for Na-ion batteries and long-cycling stability for Li-ion batteries, as elucidated by morphology differences that sodiation/desodiation brings intense nanomachine effect.