Superhalide-Anion-Motivator Reforming-Enabled Bipolar Manipulation toward Longevous Energy-Type Zn||Chalcogen Batteries.

Neutrophilic superhalide-anion-triggered chalcogen conversion-based Zn batteries, despite latent high-energy merit, usually suffer from a short lifespan caused by dendrite growth and shuttle effect. Here, a superhalide-anion-motivator reforming strategy is initiated to simultaneously manipulate the anode interface and Se conversion intermediates, realizing a bipolar regulation toward longevous energy-type Zn batteries. With ZnF2 chaotropic additives, the original large-radii superhalide zincate anion species in ionic liquid (IL) electrolytes are split into small F-containing species, boosting the formation of robust solid electrolyte interphases (SEI) for Zn dendrite inhibition. Simultaneously, ion radius reduced multiple F-containing Se conversion intermediates form, enhancing the interion interaction of charged products to suppress the shuttle effect. Consequently, Zn||Se batteries deliver a ca. 20-fold prolonged lifespan (2000 cycles) at 1 A g-1 and high energy/power density of 416.7 Wh kgSe-1/1.89 kW kgSe-1, outperforming those in F-free counterparts. Pouch cells with distinct plateaus and durable cyclability further substantiate the practicality of this design.

Hydrophobic Ion Barrier-Enabled Ultradurable Zn (002) Plane Orientation towards Long-Life Anode-Less Zn Batteries.

Gradual disability of Zn anode and high negative/positive electrode (N/P) ratio usually depreciate calendar life and energy density of aqueous Zn batteries (AZBs). Herein, within original Zn2+-free hydrated electrolytes, a steric hindrance/electric field shielding-driven "hydrophobic ion barrier" is engineered towards ultradurable (002) plane-exposed Zn stripping/plating to solve this issue. Guided by theoretical simulations, hydrophobic adiponitrile (ADN) is employed as a steric hindrance agent to ally with inert electric field shielding additive (Mn2+) for plane adsorption priority manipulation, thereby constructing the "hydrophobic ion barrier". This design robustly suppresses the (002) plane/dendrite growth, enabling ultradurable (002) plane-exposed dendrite-free Zn stripping/plating. Even being cycled in Zn‖Zn symmetric cell over 2150 h at 0.5 mA cm-2, the efficacy remains well-kept. Additionally, Zn‖Zn symmetric cells can be also stably cycled over 918 h at 1 mA cm-2, verifying uncompromised Zn stripping/plating kinetics. As-assembled anode-less Zn‖VOPO4 ⋅ 2H2O full cells with a low N/P ratio (2 : 1) show a high energy density of 75.2 Wh kg-1 full electrode after 842 cycles at 1 A g-1, far surpassing counterparts with thick Zn anode and low cathode loading mass, featuring excellent practicality. This study opens a new avenue by robust "hydrophobic ion barrier" design to develop long-life anode-less Zn batteries.

Hydrated Eutectic Electrolytes Stabilizing Quasi-Underpotential Mg Plating/Stripping for High-Voltage Mg Batteries.

Aqueous rechargeable Mg batteries (ARMBs) usually fail from severe anode passivation, alternatively, executing quasi-underpotential Mg plating/stripping chemistry (UPMC) on a proper heterogeneous metal substrate is a crucial remedy. Herein, a stable UPMC on Zn substrate is initially achieved in new hydrated eutectic electrolytes (HEEs), delivering an ultralow UPMC overpotential and high energy/voltage plateau of ARMBs. The unique eutectic property remarkably expands the lower limit of electrochemical stability window (ESW) of HEEs and undermines the competition between hydrogen evolution/corrosion reactions and UPMC, enabling a reversible UPMC. The UPMC is carefully revealed by multiple characterizations, which shows a low overpotential of 50 mV at 0.1 mA cm-2 over 550 h. With sulfonic acid-doped polyaniline (SPANI) cathodes, UPMC-based full cells show high energy/power densities of 168.6 Wh kg-1 /2.1 kWh kg-1 and voltage plateau of 1.3 V, far overwhelming conventional aqueous systems.

Hetero-Solvation-Diluted Strongly-Coordinated Zn2+ -Cosolvent Pairs Downshifting Zn Electrode Potential for High-Voltage Hybrid Batteries.

Mild aqueous Zn batteries (AZBs) generally suffer a low-voltage/energy dilemma, which compromises their competitiveness for large-scale energy storage. Pushing Zn anode potential downshift is an admissible yet underappreciated approach for high-voltage/energy AZBs. Herein, with a mild hybrid electrolyte containing in situ-derived diluted strongly-coordinated Zn2+ -cosolvent pairs, a considerable Zn anode potential downshift is initially achieved for high-voltage Zn-based hybrid batteries. The chosen butylpyridine cosolvent not only strongly coordinates Zn2+ ions but also acts as a hydrogen-bond end-capping agent to inhibit hydrogen evolution reaction (HER). The electrolyte environment with hetero-solvation-diluted strongly-coordinated Zn2+ -cosolvent pairs remarkably lowers Zn2+ activity, responsible for the Zn electrode potential downshift (-0.330 V vs Zn), confirming to modified Nernst law (ΔE = R T n F $\frac{{RT}}{{nF}}$ ln[a(Zn2 + )/a(coordinated solvent)]). With the diluted Zn2+ -containing hybrid electrolyte, the Zn//Zn symmetric cell in the hybrid electrolyte shows a long lifespan over 1270 h at a stripping/plating capacity of 0.4 mA h cm-2 . Compared with in common hybrid electrolytes, the as-assembled Zn-MnO2 hybrid battery delivers a ca. 0.278 V enhanced voltage plateau (1.57 V) and a long-term cyclability of over 736 cycles. This work opens a new avenue toward Zn anode potential downshift for high-voltage AZBs, which can extend to other mild metal batteries.

Fabrication of an electrochemical chiral sensor via an integrated polysaccharides/3D nitrogen-doped graphene-CNT frame.

We report a novel chiral interface based on polysaccharides that was integrated via an amidation reaction between the COOH of sodium alginate and the NH2 of chitosan to form a chiral selector (SA-CS) with three dimensional N-doped graphene-CNT (NGC) as the substrate material. This interface was used for chiral discrimination of tryptophan (Trp) enantiomers via electrochemical measurements. The FT-IR, SEM, TEM and XPS characterization showed that the chiral selector and substrate materials were prepared successfully. Compared with individual SA-CS and NGC, the integrated polysaccharides/3D NGC showed higher enantioselectivity for L-Trp than D-Trp due to the smaller steric hindrance for D-Trp during the formation of three-point interactions between the two diastereoisomeric enantiomer-selector complexes, which allowed L-Trp to more easily detach from the electrode modification layer and approach the electrode surface, facilitating its approach and confirming that SA-CS had a higher constant for L-Trp when applied to real samples.