A major factor in the capacity fading of lithium-ion batteries is the imbalance in the state-of-charge (SOC) between the positive and negative electrodes, which is caused by the difference in the side-reaction current between the two electrodes. Therefore, it is crucial to understand these side reactions to extend battery life. There are two types of side-reaction current, I_SR: “intrinsic”-I_SR results from electrolyte decomposition, while “additional”-I_SR results from the reaction of decomposition products. The “additional”-I_SR is closely related to crosstalk reactions. In this study, we conducted overdischarge tests on Li[Li_1/3Ti_5/3]O₄ (LTO)/Li[Li_0.1Al_0.1Mn_1.8]O₄ (LAMO) cells with the SOC of the positive and negative electrodes intentionally imbalanced to understand the nature of the “additional”-I_SR. While the cell capacity initially increased after the overdischarge, the recovered capacity decreased in subsequent cycles. This phenomenon can be explained well by a side-reaction model that considers the oxidant generated in the cell due to overdischarge, which indicates that the concentrations of oxidants and reductants in the cell are important for the I_SR.

We demonstrated that the electrogenerated chemiluminescence (ECL) performances of 5,6,11,12-tetraphenyltetracene (rubrene)-based devices can be significantly enhanced by using an emitting assist dopant. We prepared an ECL solution by dissolving rubrene and 4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB) in an organic solvent. A microfluidic ECL cell having the prepared solution exhibited a bright yellow ECL emission from rubrene with a maximum luminance of 292 cd m⁻² at 6.0 V and a maximum current efficiency of 4.50 cd A⁻¹ at 5.5 V. Moreover, a current efficiency of over 3.0 cd A⁻¹ was maintained from 3.0 to 6.5 V. Furthermore, the device lifetime was improved in comparison with the rubrene solution without DPAVB. The emission mechanism was discussed using cyclic voltammogram data. The DPAVB molecule was found to be more readily oxidized and more difficult to be reduced than rubrene. The excited rubrene molecules were expected to be produced efficiently in the device by the electron transfer reactions between rubrene^•− and DPAVB^•+ as well as rubrene^•− and rubrene^•+. Based on the findings, we concluded that the enhanced device characteristics were primarily attributed to the well-balanced generation of radical cations and anions.

Sodium-sulfur (Na-S) batteries are promising energy storage systems for renewable energy sources which redeem an intermittent energy source. This study reports the effects of the Na[SO₃CF₃] fraction in an inorganic Na[SO₃CF₃]-Cs[N(SO₂CF₃)₂] ionic liquid electrolyte (x(Na[SO₃CF₃]) = 0.2, 0.3, and 0.4) on the performance of Na-S batteries. Measurements of physicochemical and electrochemical properties demonstrated that decrease in the Na[SO₃CF₃] fraction decreases viscosity and increases ionic conductivity and the solubility of polysulfides into the ionic liquid, which contributes to the enhanced capacity in the low potential region during discharging.

Some of the Benzimidazole-linked polymers (BILPs) are a class of porous organic polymers that have high porosities, large specific surface areas, and high thermal and chemical stability. Owing to these properties, BILPs can be used in various applications including solid electrolytes for renewable energy utilization. In this study, we carried out the boran-modification of a kind of BILPs, in order to increase the Li ion conductivity by decreases the interaction between lithium ions and the anion backbone. The resulting B-TFB-HAB-BILP materials have an ionic conductivity of 2.9 × 10⁻⁶ S cm⁻¹ at 30 °C, which increases to 1.4 × 10⁻⁴ S cm⁻¹ at room temperature with the addition of the ionic liquid, PP13[TFSA]. This can be attributed to the suppression of resistance at the grain boundary. A coin cell with an organic cathode active material, B-TFB-HAB-BILP/PP13[TFSA] as the quasi-solid electrolyte, and Li foil as the anode exhibited an initial discharge capacity of 223 mAh g⁻¹ (76 % of theoretical capacity). Our study can aid in the realization of organic rechargeable batteries with high gravimetric energy density.

The pseudocapacitive flowable electrodes typically show high energy density because of the contribution of the faradaic charge of redox-active organic materials and the electric double layer charge of carbon materials. However, the redox reaction kinetics of organic molecules are slow due to poor diffusion kinetics. We recently reported that a pseudocapacitive flowable electrode exhibited bell-shaped cyclic voltammograms (peak separation (ΔE_p) = 0 mV); specifically, the molecules were confined within slit-shaped graphitic micropores of activated carbon (AC). Herein, we studied the relationship between charge storage and the reaction mechanism to tailor the electrochemical performance of a pseudocapacitive flowable electrode by half-cell study. The results show that the redox reaction of the confined molecules entailed a charge-transfer-controlled mechanism, while the unconfined molecules exhibited a mass-transfer-controlled system. This difference inhibited the fast charging and discharging of the pseudocapacitive flowable electrode. This study demonstrates that half-cell studies are crucial for clarifying the relationship between the charge storage and rate performances of pseudocapacitive flowable electrodes.

Pipecolyldithiocarbamic Acid (PIPDTC) is actually considered as a potential corrosion inhibitor. The inhibition behavior of PIPDTC is appropriately confirmed by electrochemical measurements accompanied with spectra characterization techniques and DFT calculations. The consequences point out that chemically adsorbed PIPDTC molecule is an outstanding corrosion inhibitor with corrosion efficiency of 99.87 % at 298 K and a great thermal stability ascribed to the Cu-S binding, implying that PIPDTC could be a tangible alternative as the prospective corrosion inhibitor for applications in marine industry.

A porous microneedle (PMN)-based potentiometric ion sensor for transdermal monitoring of electrolytes in the interstitial fluid was developed. The carbon coating with an ion-selective membrane was formed on half of the needle tip as the working electrode, while the Ag/AgCl reference electrode was mounted on the PMN chip. This design of a single needle-type configuration allows lower invasive transdermal sensing than the conventional system with multiple needle electrodes. The fabricated potentiometric sensor showed the near-Nernstian responses to Na⁺ concentration in the excised pig skin, demonstrating the applicability for monitoring intradermal electrolytes.