Multifactorial engineering of biomimetic membranes for batteries with multiple high-performance parameters

Lithium–sulfur (Li–S) batteries have a high specific capacity, but lithium polysulfide (LPS) diffusion and lithium dendrite growth drastically reduce their cycle life. High discharge rates also necessitate their resilience to high temperature. Here we show that biomimetic self-assembled membranes from aramid nanofibers (ANFs) address these challenges. Replicating the fibrous structure of cartilage, multifactorial engineering of ion-selective mechanical, and thermal properties becomes possible. LPS adsorption on ANF surface creates a layer of negative charge on nanoscale pores blocking LPS transport. The batteries using cartilage-like bioinspired ANF membranes exhibited a close-to-theoretical-maximum capacity of 1268 mAh g−1, up to 3500+ cycle life, and up to 3C discharge rates. Essential for safety, the high thermal resilience of ANFs enables operation at temperatures up to 80 °C. The simplicity of synthesis and recyclability of ANFs open the door for engineering high-performance materials for numerous energy technologies.

In-situ electrochemical modification of pre-intercalated vanadium bronze cathodes for aqueous zinc-ion batteries

Vanadium bronzes have been well-demonstrated as promising cathode materials for aqueous zinc-ion batteries. However, conventional single-ion pre-intercalated V2O5 nearly reached its energy/power ceiling due to the nature of micro/electronic structures and unfavourable phase transition during Zn2+ storage processes. Here, a simple and universal in-situ anodic oxidation method of quasi-layered CaV4O9 in a tailored electrolyte was developed to introduce dual ions (Ca2+ and Zn2+) into bilayer δ-V2O5 frameworks forming crystallographic ultra-thin vanadium bronzes, Ca0.12Zn0.12V2O5·nH2O. The materials deliver transcendental maximum energy and power densities of 366 W h kg−1 (478 mA h g−1 @ 0.2 A g−1) and 6627 W kg−1 (245 mA h g−1 @ 10 A g−1), respectively, and the long cycling stability with a high specific capacity up to 205 mA h g−1 after 3000 cycles at 10 A g−1. The synergistic contributions of dual ions and Ca2+ electrolyte additives on battery performances were systematically investigated by multiple in-/ex-situ characterisations to reveal reversible structural/chemical evolutions and enhanced electrochemical kinetics, highlighting the significance of electrolyte-governed conversion reaction process. Through the computational approach, reinforced “pillar” effects, charge screening effects and regulated electronic structures derived from pre-intercalated dual ions were elucidated for contributing to boosted charge storage properties.

A Facile Synthesis of PbS-G QDs Nanocomposite as Electrode Material With Enhanced Energy Density for High Performance Supercapattery Application

Bare PbS QDs and PbS-GQDs nanocomposite were prepared by chemical methods for supercapattery application and characterized by suitable analytical techniques confirming the formation of PbS-GQDs nanocomposite. The electrochemical performance of the fabricated electrodes showed that the PbS-GQDs nanocomposite exhibited high specific capacity, energy and power densities of 577.94 C g-1 , 166.45 Wh kg-1 and 576.01 W kg-1 respectively at 2 A g-1 compared to that of bare PbS QDs. The enhanced electrochemical performance of PbS-GQDs can be associated with the conductive platform provided by synergistic effect of GQDs. The nonlinearity in charge and discharge curves confirms the supercapattery behaviour of the nanocomposite. Also, PbS-G QDs nanocomposite electrode showed highly cyclic stability compared to bare PbS QDs after 5000 cycles. The results emphasize the potential of PbS-G QDs nanocomposite as a stable active electrode material for energy storage application.

Electrode material based on multilayer graphene oxide for chemical current sources

The results of the studies of the electrochemical synthesis of multilayer graphene oxide were presented, and the possibility of using it as an electrode material of the supercapacitor was shown. In an alcohol suspension the thickness of the particles of multilayer graphene oxide was less than 0.1 µm with an area of more than 100 µm2. The graphene oxide-based electrode has a high specific capacity of 107 F·g−1 and a high charge retention rate of 97% after 5000 cycles. It was shown that the graphene oxide electrode had a maximum specific energy of 8.7 W·h·kg−1 at the current density of 0.1 A·g−1 and had a maximum power of 2291.1 W·kg−1 at the current density of 4 A·g−1. The application of a lithium-thionyl chloride cell with a multilayer graphene oxide cathode on a nickel grid was tested. It was found that graphene oxide synthesized using the electrochemical method is a promising electrode material for creating a symmetric supercapacitor.

Facile Hydrothermal Synthesis and Supercapacitor Performance of Mesoporous Necklace-Type ZnCo2O4 Nanowires

In this work, mesoporous ZnCo2O4 electrode material with necklace-type nanowires was synthesized by a simple hydrothermal method using water/ethylene glycol mixed solvent and subsequent calcination treatment. The ZnCo2O4 nanowires were assembled by several tiny building blocks of nanoparticles which led to the growth of necklace-type nanowires. The as-synthesized ZnCo2O4 nanowires had porous structures with a high surface area of 25.33 m2 g−1 and with an average mesopore of 23.13 nm. Due to the higher surface area and mesopores, the as-prepared necklace-type ZnCo2O4 nanowires delivered a high specific capacity of 439.6 C g−1 (1099 F g−1) at a current density of 1 A g−1, decent rate performance (47.31% retention at 20 A g−1), and good cyclic stability (84.82 % capacity retention after 5000 cycles). Moreover, a hybrid supercapacitor was fabricated with ZnCo2O4 nanowires as a positive electrode and activated carbon (AC) as a negative electrode (ZnCo2O4 nanowires//AC), which delivered an energy density of 41.87 Wh kg−1 at a power density of 800 W kg−1. The high electrochemical performance and excellent stability of the necklace-type ZnCo2O4 nanowires relate to their unique architecture, high surface area, mesoporous nature, and the synergistic effect between Zn and Co metals.