Portable electronic devices (PEDs) are promising information‐exchange platforms for real‐time responses. Their performance is becoming more and more sensitive to energy consumption. Rechargeable batteries are the primary energy source of PEDs and hold the key to guarantee their desired performance stability. With the remarkable progress in battery technologies, multifunctional PEDs have constantly been emerging to meet the requests of our daily life conveniently. The ongoing surge in demand for high‐performance PEDs inspires the relentless pursuit of even more powerful rechargeable battery systems in turn. In this review, we present how battery technologies contribute to the fast rise of PEDs in the last decades. First, a comprehensive overview of historical advances in PEDs is outlined. Next, four types of representative rechargeable batteries and their impacts on the practical development of PEDs are described comprehensively. The development trends toward a new generation of batteries and the future research focuses are also presented.

Aluminum-ion batteries (AIBs) are regarded as viable alternatives to lithium-ion technology because of their high volumetric capacity, their low cost, and the rich abundance of aluminum. However, several serious drawbacks of aqueous systems (passive film formation, hydrogen evolution, anode corrosion, etc.) hinder the large-scale application of these systems. Thus, nonaqueous AIBs show incomparable advantages for progress in large-scale electrical energy storage. However, nonaqueous aluminum battery systems are still nascent, and various technical and scientific obstacles to designing AIBs with high capacity and long cycling life have not been resolved until now. Moreover, the aluminum cell is a complex device whose energy density is determined by various parameters, most of which are often ignored, resulting in failure to achieve the maximum performance of the cell. The purpose here is to discuss how to further develop reliable nonaqueous AIBs. First, the current status of nonaqueous AIBs is reviewed based on statistical data from the literature. The influence of parameters on energy density is analyzed, and the current situation and existing problems are summarized. Furthermore, possible solutions and concerns regarding the construction of reliable nonaqueous AIBs are comprehensively discussed. Finally, future research directions and prospects in the aluminum battery field are proposed.

The 'composite' layered materials for lithium-ion batteries have recently attracted great attention owing to their large discharge capacities. Here, the 0.5Li(2)MnO(3)·0.5LiMn(0.42)Ni(0.42)Co(0.16)O(2)'composite' layered manganese-rich material is prepared and characterized by the synchrotron X-ray powder diffraction (SXPD). The relationship between its electrochemical performance and its 'composite' components, the Li(2)MnO(3) phase activation process during cycling and the cycle stability of this material at room temperature are elucidated based on its kinetic controlled electrochemical properties, dQ/dV curves and Raman scattering spectroscopies associated with different initial charge-discharge current densities (5 mA g(-1), 20 mA g(-1) and 50 mA g(-1)), cut-off voltages (4.6 V and 4.8 V) and cycle numbers (50 cycles and 150 cycles). Furthermore, its reaction pathways are tracked via a firstly introduced integrated compositional phase diagram of four components, Li(2)MnO(3), LiMn(0.42)Ni(0.42)Co(0.16)O(2), MO(2) (M = Mn(1-α-β)Ni(α)Co(β); 0 ≤α≤ 5/12, 0 ≤β≤ 1/6) and LiMnO(2), which turns out to be a very important guiding tool for understanding and utilizing this 'composite' material.

Organic electrode materials are promising alternatives to transition-metal based intercalation compounds for the next generation of high-performance and sustainable batteries. Herein, a novel quinone-based organic, lithium salt of poly(2,5-dihydroxy-p-benzoquinonyl sulfide) (Li 2 PDHBQS), was successfully synthesized through a simple one-step polycondensation reaction, and applied as a cathode for Li-organic batteries. As an oligomeric lithium salt with average polymerization degree of 7, Li 2 PDHBQS combines the advantages of the O/Li/O coordination bond and increased molecular weight, thus solves absolutely the dissolution problem of active material in non-aqueous electrolytes, which has seriously hindered development of organic electrode materials. Benefiting from the high theoretical capacity, intrinsic insolubility, fast reaction kinetics of the quinone group, accelerated Li-ion transport and uniform blending with conductive carbon, as well as the stable amorphous structure, Li 2 PDHBQS shows superior comprehensive electrochemical performance including high reversible capacity (268 mA h g À1 ), high cycling stability (1500 cycles, 90%), high rate capability (5000 mA g À1 , 83%) andhigh Coulombic efficiency (99.9-100.1%). Investigation of the structure-property relationship of Li 2 PDHBQS and its analogues also gives new insights into developing novel quinone-based organic electrode materials, for building better Li-organic or Na-organic batteries beyond traditional Li-ion batteries. Broader contextAll electroactive organics or polymers involving reversible redox reactions have the potential to be applied as organic electrode materials for rechargeable batteries. Aer nearly half a century's exploration, conjugated carbonyl compounds are recognized as one of the most promising types among various electroactive materials, as only they have the potential to achieve simultaneously high energy density, high cycling stability and high power density. The conjugated carbonyl compounds can be divided into small organic molecules, organic polymers and organic salts according to the molecular structure, or quinones, dianhydrides, carboxylates, diketones and so on according to the electroactive group. Usually the redox potential of conjugated carbonyl compounds is between 1.5 and 3.0 V vs. Li + /Li, but carboxylates show relatively low redox potential below 1.0 V vs. Li + /Li, so they have the potential to be applied as either cathode or anode. As the theoretical specic capacity is up to 600 mA h g À1 , it is possible to achieve high energy density, although the redox potential is much lower than that of conventional inorganic cathodes. Research on this topic mainly focuses on solving the dissolution problem of active materials to improve the cycling stability, as well as developing new organic electrode materials with higher energy density.

About phase: The coexistence of rhombohedral LiTMO2 (TM=Ni, Co, or Mn) and monoclinic Li2MnO3-like structures inside Li1.2Mn0.567Ni0.166Co0.067O2 is revealed directly at atomic resolution. The hetero-interface along the [001]rh/[103]mon zone axis direction is demonstrated, indicating the two-phase nature of these lithium-rich cathode materials (green Li, blue Mn, red O, cyan TM).