Trihigh tricontinuous graphene cathode enables a 1.1 s charge, 250,000 cycle life, wide temperature range Al-ion battery.

A conceptually new defect-free principle is proposed for designing graphene cathode of aluminum-ion battery: the fewer the defects, the better the performances. Developed through scalable approach, defect-free graphene aerogel cathode affords high capacity of 100 mAh g under an ultrahigh rate of 500 C, exceeding defective graphene and previous reports. This defect-free principle can guide us to fabricate better graphene-based electrodes.

Graphene aerogel microlattices (GAMs) hold great prospects for many multifunctional applications due to their low density, high porosity, designed lattice structures, good elasticity, and tunable electrical conductivity. Previous 3D printing approaches to fabricate GAMs require either high content of additives or complex processes, limiting their wide applications. Here, a facile ion‐induced gelation method is demonstrated to directly print GAMs from graphene oxide (GO) based ink. With trace addition of Ca2+ ions as gelators, aqueous GO sol converts to printable gel ink. Self‐standing 3D structures with programmable microlattices are directly printed just in air at room temperature. The rich hierarchical pores and high electrical conductivity of GAMs bring admirable capacitive performance for supercapacitors. The gravimetric capacitance (Cs) of GAMs is 213 F g−1 at 0.5 A g−1 and 183 F g−1 at 100 A g−1, and retains over 90% after 50 000 cycles. The facile, direct 3D printing of neat graphene oxide can promote wide applications of GAMs from energy storage to tissue engineering scaffolds.

Carbon aerogels demonstrate wide applications for their ultralow density, rich porosity, and multifunctionalities. Their compressive elasticity has been achieved by different carbons. However, reversibly high stretchability of neat carbon aerogels is still a great challenge owing to their extremely dilute brittle interconnections and poorly ductile cells. Here we report highly stretchable neat carbon aerogels with a retractable 200% elongation through hierarchical synergistic assembly. The hierarchical buckled structures and synergistic reinforcement between graphene and carbon nanotubes enable a temperature-invariable, recoverable stretching elasticity with small energy dissipation (~0.1, 100% strain) and high fatigue resistance more than 106 cycles. The ultralight carbon aerogels with both stretchability and compressibility were designed as strain sensors for logic identification of sophisticated shape conversions. Our methodology paves the way to highly stretchable carbon and neat inorganic materials with extensive applications in aerospace, smart robots, and wearable devices.

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Aluminum metal foil is the optimal choice as an anode material for aluminum-ion batteries for its key advantages such as high theoretical capacity, safety, and low cost. However, the metallic nature of aluminum foil is very likely to induce severe dendrite growth with further electrode disintegration and cell failure, which is inconsistent with previous reports. Here, we discover that it is aluminum oxide film that efficiently restricts the growth of crystalline Al dendrite and thus improves the cycling stability of Al anode. The key role of surficial aluminum oxide film in protecting Al metal anode lies in decreasing the nucleation sites, controlling the metallic dendrite growth, and preventing the electrode disintegration. The defect sites in aluminum oxide film provide channels for electrolyte infiltration and further stripping/depositing. Attributed to such a protective aluminum oxide film, the Al-graphene full cells can attain up to 45 000 stable cycles.

Aqueous rechargeable batteries are highly safe, low‐cost, and environmentally friendly, but restricted by low energy density. One of the most efficient solutions is to improve the concentration of the aqueous electrolytes. However, each salt is limited by its physical solubility, generally below 21–32 mol kg−1 (m). Here, a ZnCl2/ZnBr2/Zn(OAc)2 aqueous electrolyte with a record super‐solubility up to 75 m is reported, which breaks through the physical solubility limit. This is attributed to the formation of acetate‐capped water–salt oligomers bridged by Br−/Cl−‐H and Br−/Cl−/O‐Zn2+ interactions. Mass spectrometry indicates that acetate anions containing nonpolarized protons prohibit the overgrowth and precipitation of ionic oligomers. The polymer‐like glass transition temperature of such inorganic electrolytes is found at ≈−70 to −60 °C, without the observation of peaks for salt‐crystallization and water‐freezing from 40 to −80 °C. This supersoluble electrolyte enables high‐performance aqueous dual‐ion batteries that exhibit a reversible capacity of 605.7 mAh g−1, corresponding to an energy density of 908.5 Wh kg−1, with a coulombic efficiency of 98.07%. In situ X‐ray diffraction and Raman technologies reveal that such high ionic concentrations of the supersoluble electrolyte enable a stage‐1 intercalation of bromine into macroscopically assembled graphene cathode.

Shape memory polymers (SMPs) change shapes as-designed through altering the chain segment movement by external stimuli, promising wide uses in actuators, sensors, drug delivery, and deployable devices. However, the recovery speed of SMPs is still far slower than the benchmark shape memory alloys (SMAs), originating from their intrinsic poor heat transport and retarded viscoelasticity of polymer chains. In this work, monolithic nanocomposite aerogels composed of bicontinuous graphene and SMP networks are designed to promote the recovery time of SMP composites to a record value of 50 ms, comparable to the SMA case. The integration of a stretchable graphene framework as a fast energy transformation grid with ultrathin polycaprolactone nanofilms (tunable at 2.5−60 nm) enables the rapid phase transition of SMPs under electrical stimulation. The graphene−SMP nanocomposite aerogels, with a density of ∼10 mg cm −3 , exhibit a fast response (175 ± 40 mm s −1 ), large deformation (∼100%), and a wide response bandwidth (0.1−20 Hz). The ultrafast response of SMP nanocomposite aerogels confers extensive uses in sensitive fuses, micro-oscillators, artificial muscles, actuators, and soft robotics. The design of bicontinuous ultralight aerogels can be extended to fabricate multifunctional and multiresponsive hybrid materials and devices.