A biospecies-derived genomic DNA hybrid gel electrolyte for electrochemical energy storage.

Intrinsic impediments, namely weak mechanical strength, low ionic conductivity, low electrochemical performance, and stability have largely inhibited beyond practical applications of hydrogels in electronic devices and remains as a significant challenge in the scientific world. Here, we report a biospecies-derived genomic DNA hybrid gel electrolyte with many synergistic effects, including robust mechanical properties (mechanical strength and elongation of 6.98 MPa and 997.42%, respectively) and ion migration channels, which consequently demonstrated high ionic conductivity (73.27 mS/cm) and superior electrochemical stability (1.64 V). Notably, when applied to a supercapacitor the hybrid gel-based devices exhibit a specific capacitance of 425 F/g. Furthermore, it maintained rapid charging/discharging with a capacitance retention rate of 93.8% after ∼200,000 cycles while exhibiting a maximum energy density of 35.07 Wh/kg and a maximum power density of 193.9 kW/kg. This represents the best value among the current supercapacitors and can be immediately applied to minicars, solar cells, and LED lightning. The widespread use of DNA gel electrolytes will revolutionize human efforts to industrialize high-performance green energy.

Inorganic-Organic Double Network Ionogels Based on Silica Nanoparticles for High-Temperature Flexible Supercapacitors.

Herein, we demonstrate an inorganic-organic double network gel electrolyte consisting of a silica particle network and a poly-2-hydroxyethyl methacrylate network in which 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquids are confined. The as-synthesized double network ionogel electrolytes exhibited high ion conductivity of 3.8 to 12.8 mS cm-1 over a wide temperature range of 30 to 150 °C and mechanical integrity with a maximum toughness of 1.8 MJ m-3 at 30 °C. These remarkable properties of the ionogel were associated with the formation of an optimal physical network of the silica nanoparticles in the colloidal dispersion. Accordingly, a flexible supercapacitor using ionogel electrolytes and reduced graphene oxide electrodes delivered energy and power densities of 48 Wh kg-1 and 4 kW kg-1, respectively, even at a high temperature of 120 °C, demonstrating excellent long-term stability that retains 93% of the initial capacitance even over 10,000 charge/discharge cycles at 120 °C.

Transport and Durability of Energy Storage Materials Operating at High Temperatures.

Temperature is a state variable that significantly affects thermodynamic and kinetic performances and performance degradation of energy storage materials. In this Perspective, we address our recent progress in the energy storage performance and transporting phenomena of supercapacitors when temperatures are elevated to >100 °C. Electrodes include reduced graphene oxide film and foam and conductive metal organic frameworks; electrolytes include phosphoric-acid-doped polybenzimidazole and double networked ionogels. The electrochemical, thermal, and mechanical properties of electrodes and electrolytes are correlated with energy storage performance and degradation at high temperatures. We also address the fundamental understanding of ion transport of polymeric electrolytes and the emergence of nanoscale-confined fast mobile protons at elevated temperatures.

Interfacially Polymerized Polyamide Interlayer onto Ozonated Carbon Nanotube Networks for Improved Stability of Sulfur Cathodes.

Lithium-sulfur (Li-S) batteries are considered promising energy-storage devices owing to the high specific capacity and low cost of the S cathode. However, they suffer from capacity decay and poor coulombic efficiency arising from the dissolution of long-chain polysulfides and their shuttling. A facile and scalable method was developed to directly coat a thin (≈57.3 nm) and porous polyamide (PA) interlayer onto a S cathode by interfacial polymerization. This PA interlayer prevented the shuttling of polysulfides by creating a physical barrier and, through chemical interactions between the amide functionalities of PA and the polysulfides, allowing access to the S electrode by the Li ions. The resulting PA-coated cathode exhibited approximately 64.2 % capacity retention over 1000 cycles at 1 C with only 0.0358 % decay per cycle and a moderate capacity of 1008 mAh g-1 at 0.1 C.