Improving the ionic conductivity of polymer electrolytes induced by ceramic nanowire fillers with abundant lithium vacancies.

The addition of ceramic fillers is regarded as an effective strategy for enhancing the ionic conductivity of polymer electrolytes. However, particulate fillers typically fail to provide continuous conductive pathways and effective reinforcement. Herein, we report a ceramic nanowire filler with long-range interfacial conductivity and abundant lithium vacancies for a poly(ethylene oxide) (PEO)-based all-solid-state polymer electrolyte. LLZO nanowires (LLZO NWs) with a high aspect ratio are synthesized by combining sol-gel electrospinning and the multi-step process involving pre-oxidation, pre-sintering, and secondary sintering, resulting in a high tensile strength of the composite electrolyte (6.87 MPa). Notably, tantalum-aluminum co-substituted LLZO NWs (TALLZO NWs) release abundant lithium vacancies, further enhancing the Lewis acid-base properties, leading to a rapid ion migration speed (Li+ transfer number = 0.79) and significantly high ionic conductivity (3.80 × 10-4 S cm-1). Due to the synergistic effect of nanostructure modification and heteroatom co-doping, the assembled all-solid-state lithium-sulfur battery exhibits a high initial discharge capacity (776 mA h g-1 at 25 °C), remarkable rate capability, and excellent cycling performance (81% capacity retention after 200 cycles at 0.1C).

Polymer Coating with Balanced Coordination Strength and Ion Conductivity for Dendrite-Free Zinc Anode.

Decorating Zn anodes with functionalized polymers is considered as an effective strategy to inhibit dendrite growth. However, this normally brings extra interfacial resistance rendering slow reaction kinetics of Zn2+ . Herein, a poly(2-vinylpyridine) (P2VP) coating with modulated coordination strength and ion conductivity for dendrite-free Zn anode is reported. The P2VP coating favors a high electrolyte wettability and rapid Zn2+ migration speed (Zn2+ transfer number, tZn 2+ = 0.58). Electrostatic potential calculation shows that P2VP mildly coordinates with Zn2+ (adsorption energy = -0.94 eV), which promotes a preferential deposition of Zn along the (002) crystal plane. Notably, the use of partially (26%) quaternized P2VP (q-P2VP) further reduces the interfacial resistance to 126 Ω, leading to a high ion migration speed (tZn 2+ = 0.78) and a considerably low nucleation overpotential (18 mV). As a result of the synergistic effect of mild coordination and partial electrolysis, the overpotential of the q-P2VP-decorated Zn anode retains at a considerably low level (≈46 mV) over 1000 h at a high current density of 10 mA cm-2 . The assembled (NH4 )2 V6 O16 ·1.5H2 O || glass fiber || q-P2VP-Zn full cell reveals a lower average capacity decay rate of only 0.018% per cycle within 500 cycles at 1 A g-1 .

Integrated Construction Improving Electrochemical Performance of Stretchable Supercapacitors Based on Ant-Nest Amphiphilic Gel Electrolytes.

Aqueous integrated stretchable supercapacitors (ISSCs) have attracted extensive attention due to the intrinsic safety in future wearable electronics. However, aqueous ISSCs usually suffer from low energy density and poor dynamic deformation stability owing to the conventional hydrogel electrolytes' narrow electrochemical stability window (ESW) and dissatisfied interface bonding. Herein, an ant-nest amphiphilic polyurethane hydro/organogel electrolyte (sAPUGE) with a wide ESW (≈2.2 V) and superb self-adhesion is prepared by electrospinning, which interacts with carbon-based stretchable electrodes for the construction of flame-retardant PU-based sAPUGE-ISSC. Benefitting from the synergistic effect of chemical bonding and mechanical meshing between the electrode and gel electrolyte interface, as-assembled sAPUGE-ISSC delivers a high energy density of 13.7 mWh cm-3 (at a power density of 0.126 W cm-3 ) and outstanding dynamic deformation stability (98.3% capacitance retention after 500 stretching cycles under 100% strain). This unique hydro/organogel electrolyte provides a pathway toward the next generation of wearable energy products in modern electronics.

Stretchable sodium-ion capacitors based on coaxial CNT supported Na2Ti3O7 with high capacitance contribution.

Stretchable sodium-ion capacitors (SSICs) are promising energy storage devices for wearable electronic devices, and the development bottleneck is the realization of stretchable battery-type electrodes with desirable electrochemical properties during dynamic deformation. Herein, we find that electrostatic modification of acidified carbon nanotubes with polyamines can introduce active sites and modulate the surface pH microenvironment, thereby developing a route to realize the in situ coaxial nanometerization of sodium titanate (nCNT@NTO). The nCNT@NTO anode material has a fast Na+ transport and the high capacitive contribution, which can deliver a high specific capacity (206.5 mA h g-1 at 0.1 A g-1) and high rate performance (maintain 51% capacity at 10 A g-1), and the ideal cycle stability (∼93% capacity retention after 1000 cycles at 5 A g-1). In addition, acrylate-rubber with high stickiness and stretchability are served as the elastic matrix both of the stretchable electrodes and quasi-solid-state electrolytes, which endows strong adhesion between electrodes and electrolytes. Thus, the accordingly assembled SSIC delivers high energy density of 8.8 mW h cm-3 (at a power density of 0.024 W cm-3), and excellent deformation stability (89% capacitance retention after 500 stretching cycles under 100% strain).

High-Performance-Integrated Stretchable Supercapacitors Based on a Polyurethane Organo/Hydrogel Electrolyte.

Stretchable supercapacitors (SSCs) are promising energy storage devices for emerging wearable electronics. However, the low-energy density and poor deformation performance are still a challenge. Herein, an amphiphilic polyurethane-based organo/hydrogel electrolyte (APUGE) with a H2O/AN-in-salt (H2O/AN-NaClO4) is prepared for the first time. The as-prepared APUGE shows a wide voltage window (∼2.3 V), good adhesion, and excellent resilience. In addition, the intrinsically stretchable electrodes are prepared by coating the activated carbon slurry onto the PU/carbon black/MWCNT conductive elastic substrate. Based on the strong interface adhesion of the PU matrix, the as-assembled SSC delivers high-energy density (5.65 mW h cm-3 when the power density is 0.0256 W cm-3) and excellent deformation stability with 94.5% capacitance retention after 500 stretching cycles at 100% strain. This fully integrated construction concept is expected to be extended to multisystem stretchable metal ion batteries, stretchable lithium-sulfur batteries, and other stretchable energy storage devices.