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The flourishing development of multifunctional flexible electronics cannot leave the beneficial role of nature, which provides continuous inspiration in their material, structural, and functional designs. During the evolution of flexible electronics, some originated from nature, some were even beyond nature, and others were implantable or biodegradable eventually to nature. Therefore, the relationship between flexible electronics and nature is undoubtedly vital since harmony between nature and technology evolution would promote the sustainable development. Herein, materials selection and functionality design for flexible electronics that are mostly inspired from nature are first introduced with certain functionality even beyond nature. Then, frontier advances on flexible electronics including the main individual components (i.e., energy (the power source) and the sensor (the electric load)) are presented from nature, beyond nature, and to nature with the aim of enlightening the harmonious relationship between the modern electronics technology and nature. Finally, critical issues in next‐generation flexible electronics are discussed to provide possible solutions and new insights in prospective exploration directions. [ABSTRACT FROM AUTHOR]

• A flexible aqueous Al-ion battery was reported for the first time. • The flexible Al-ion battery exhibits exceptional flexibility and safety. • The Al-ion battery delivers excellent electrochemical cycling stability. • This work paves the way for Al-ion battery application in wearable electronics. With the fast development of flexible and wearable electronics, the design of secondary energy storage system based on aqueous metal ion battery with outstanding flexibility, safety and low cost is critical for their practical application. As low-cost alternatives to lithium ion battery, multivalent metal ion technologies including Mg2+, Zn2+, Ca2+, and Al3+ are investigated increasingly in the past few years. The investigation based on Al-ion chemistry is also underway considering the aluminum's advantages of natural abundance, small ion size together with three-electron-redox properties. Herein, a flexible aqueous Al-ion battery is successfully fabricated for the first time with copper hexacyanoferrate cathode and polypyrrole (PPy) coated MoO 3 anode sandwiched by gel electrolyte. The as-assembled Al-ion battery based on intercalation chemistry exhibits an excellent cycling stability of 83.2% capacity retention after 100 cycles and good rate capability benefiting from the conductive PPy coating layer on MoO 3 anode. Besides, the battery demonstrates impressive flexibility and safety to sustain various deformations and mechanical abuse including bending, squeezing, folding, twisting as well as arbitrary drilling and tailoring into any desired shapes. Obviously, the flexible aqueous Al-ion battery developed in this study paves the way of multivalent metal ion battery as energy storage device towards various wearable electronics. [ABSTRACT FROM AUTHOR]

• A unique silane coupling agent derivative-coated Zn anode with ion perselectivity was demonstrated. • This modified Zn anode greatly restrained side reaction with desolvation of [Zn(H 2 O)6]2−. • Versatile coating with tightly contact of nano particles and organic network contributed to full-cell long cycling life. Although zinc anodes are extensively adopted to meet aqueous energy storage, serious dendrite formation and side reaction resulting in inferior lifetime have hindered the application. In this work, a unique interfacial engineering is proposed by a self-assembled artificial layer tightly contact to the surface of zinc anode with Zn2+ permselectivity. Such artificial layer via a facile hydrolysis consists of nano inorganic particles well dispersed in organic network. The screening for the bound water of Zn2+ enables excellent anticorrosion during cycling and rest situation. Meanwhile, the modified zinc anode can reduce the Zn2+ nucleation barrier for uniform distribution, which is beneficial to dendrite suppression. Consequently, the modified zinc anodes in both symmetric and full cells exhibit prominently electrochemical reversibility. Specifically, with a cycling area capacity of 3.0 mAh cm−2 at 1.0 mA cm−2, the modified zinc anode can tolerate superior plating/stripping behavior over 1000 h. When it is coupled with vanadium pentoxide cathode, the performance advantage of the modified full-cell is still impressive and high-capacity retention of ∼84 % after 1200 cycles is achieved. [ABSTRACT FROM AUTHOR]

The loofah-like LaMnO 3 perovskite is for the first time demonstrated to be cathode material for ZIBs with long cycle life. [Display omitted] Due to high safety and excellent rate performance, the aqueous Zn-ion battery is a promising energy storage battery for practical application. However, most manganese-based compounds suffer from poor cycling and rate performance. Herein, a new concept of Zn-ions battery is assembled with the loofah-like LaMnO 3 perovskite as a novel cathode, achieving fast ion kinetics through the co-intercalation of Zn2+ and H+ cations. In this work, the Ni-doping strategy is adopted to improve the electrochemical performance of LaMnO 3 perovskite as a cathode material for Zn-ion batteries. The resultant LaNi x Mn 1-x O 3 (x = 0.2) exhibits a superior capacity of 226 mAh g−1 after 80 cycles at 100 mA g−1 and high working voltages at 1.4 V and 1.26 V vs. Zn2+/Zn in the electrolyte of 2 M ZnSO 4 + 0.2 M MnSO 4. Even at 500 mA g−1, the new Zn/LaNi x Mn 1-x O 3 battery still delivers a discharge capacity of 113 mAh g−1 after 1000 cycles. At medium current density, the electrochemical process of the LaNi x Mn 1-x O 3 (x = 0.2) electrode is co-controlled by the solid diffusive and surface-capacitive process with a fast ion diffusion rate. The lanthanum manganese perovskite is a potential cathode material for Zn-ion batteries with long cycle performance and high rate cyclability. This work significantly opens up the way of perovskite materials as new cathodes for high-rate ZIBs. [ABSTRACT FROM AUTHOR]

Highlights: A 2.4 V high-voltage flexible aqueous ZIB was fabricated, and superiors performances were achieved: extremely flat charging/discharging voltage plateaus (1.9/1.8 V), the smallest plateau voltage gap of 0.1 V, high energy density of 120 Wh kg−1, high power density of 3700 W kg−1, and excellent rate capability of 25 C. The battery posed application potential in wearable electronics with extreme safety against tough destructions including hammering, sewing, punching, and soaking. Flexible rechargeable aqueous zinc-ion batteries (ZIBs) have attracted extensive attentions in the energy storage field due to their high safety, environmental friendliness, and outstanding electrochemical performance while the exploration of high-voltage aqueous ZIBs with excellent rate capability is still a great challenge for the further application them in flexible and wearable electronics. Herein, we fabricated a 2.4 V high-voltage flexible aqueous ZIB, being among the highest voltage reported in aqueous ZIBs. Moreover, it exhibits extremely flat charging/discharging voltage platforms and the dropout voltage is only 0.1 V, which is the smallest gap in all aqueous batteries to our best knowledge. Furthermore, the prepared ZIB performs high rate capability of 25 C and energy density of 120 Wh kg−1 and exhibits excellent safety under various destructive conditions including hammering, sewing, punching, and soaking. These extraordinary results indicate the great application potential of our high-voltage flexible aqueous ZIB in wearable electronics. [ABSTRACT FROM AUTHOR]

• Organic-inorganic Ov-PVO/G heterostructures are prepared via a ball-milling approach. • The heterostructures contain expanded interlayer spacing, oxygen vacancy and heterointerface. • Freestanding Ov-PVO/G heterostructure cathodes with high mass-loading are fabricated. • The three-in-one Ov-PVO/G heterostructures exhibit accelerated reaction kinetics. • The freestanding Ov-PVO/G heterostructure cathodes for AZIBs deliver high areal capacity. Aqueous Zn-ion batteries (AZIBs) have great potential in large-scale energy storage, however, developing suitable cathodes with high energy/power densities remains highly challenging. Herein, a unique organic-inorganic heterostructures (denoted as O v -PVO/G) of poly(3,4-ethylenedioxythiophene) intercalated V 2 O 5 nanocrystals anchored on few-layer graphene by a simple and scalable ball-milling approach are demonstrated for high areal-capacity AZIBs cathodes, in which, adjusted interlayer spacing, abundant oxygen vacancies and robust heterointerfaces can be simultaneously constructed. Moreover, the feature of being well dispersed in different polar solvents (H 2 O, NMP, etc.) enable facile incorporation of the O v -PVO/G heterostructures into conductive networks of single-walled carbon nanotubes to fabricate freestanding composite cathodes. Electrochemical measurement and first-principles calculations indicate that such "Three-in-One" heterostructure can significantly enhance Zn2+ adsorption/desorption, electrical conductivity and charge transfer due to strong synergy, thereby exhibiting high-capacity and accelerated reaction kinetics during cycling. Specifically, at a practical mass loading of 12.0 mg/cm2, the freestanding O v -PVO/G cathodes show a high areal-capacity of 6.1 mAh/cm2 at 2.4 mA/cm2 and works stable with an area-capacity of 1.63 mAh/cm2 at 120 mA/cm2 after 500 cycles. More importantly, flexible soft-packaged AZIBs based on 3×3 cm2 high mass-loading O v -PVO/G cathodes deliver record-high and stable electric energy beyond 21.5 mAh at different bending states. This work paves a more promising way to practical application of high-performance AZIBs. [ABSTRACT FROM AUTHOR]

The rechargeable Lithium-Sulfur battery has been regarded as a promising candidate for the next generation energy storage devices owing to its high energy density, low cost and environment friendliness. The further development of Li-S battery, however, is still hindered by capacity decay and kinetics sluggish caused by the poor electrochemical activity and polysulfide shuttle effect. Herein, a nitrogen-doped porous carbon framework is synthesized by a facial strategy, delivering large special surface area and narrow pore size distribution. As a result, the composited cathode with sulfur loading of 62% shows an excellent rate performance and extreme cycling stability (100 cycles at 1.0 C and 457 mAh g −1 after 500 cycles at 2.0 C), which demonstrates that the N-doped porous carbon host can effectively improve the transport of electron and ion, entrap the dissolved polysulfide, thus improving the electrochemical performance significantly in rate performance and cycle stability. [ABSTRACT FROM AUTHOR]