A 3D network gel polymer electrolyte (3D-GPE) is designed for lithium metal batteries and prepared by an initiator-free one-pot ring-opening polymerization technique. This 3D-GPE exhibits an unprecedented combination of mechanical strength, ionic conductivity, and more importantly, effective suppression of Li dendrite growth. The produced lithium-based battery presents long life, high rate, and excellent safety.

The increasing demands of energy storage require the significant improvement of current Li-ion battery electrode materials and the development of advanced electrode materials. Thus, it is necessary to gain an in-depth understanding of the reaction processes, degradation mechanism, and thermal decomposition mechanisms of electrode materials under realistic operation conditions. This understanding can be obtained by in situ/operando characterization techniques that provide information on the structure evolution, redox mechanism, solid-electrolyte interphase (SEI) formation, side reactions and Li-ion transport properties under operating conditions. Here, the recent developments in the in situ/operando techniques employed for the investigation of the structural stability, dynamic properties, chemical environment changes and morphological evolution during electrochemical processes are described and summarized in detail. The experimental approaches reviewed in this paper include X-ray, electron, neutron, optical, and scanning probes. Each advanced technique has unique capabilities to study specific properties of electrode materials within specific limitations. The experimental methods and operating principles, especially the in situ cell designs, are described in detail. To illustrate the applicability and uniqueness of each technique, representative studies making use of the in situ/operando techniques are discussed and summarized. Finally, the major current challenges and future opportunities of the in situ/operando techniques are discussed. Several important battery challenges are likely to benefit from these in situ/operando techniques, including the inhomogeneous reactions of This article is protected by copyright. All rights reserved. 4high energy density cathodes, the development of safe and reversible Li metal plating and the development of stable SEI on electrodes.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

A novel composite polymer electrolyte (CPE) with nano-SiO2 acted as a cross-linking agent to form a 3D cross-linked network with improved electrochemical stability.

The booming development of electronics, electric vehicles, and grid storage stations has led to a high demand for advanced energy‐storage devices (ESDs) and accompanied attention to their reliability under various circumstances. Self‐healing is the ability of an organism to repair damage and restore function through its own internal vitality. Inspired by this, brilliant designs have emerged in recent years using self‐healing materials to significantly improve the lifespan, durability, and safety of ESDs. Extrinsic and intrinsic self‐healing materials and their working principles are first introduced. Then, the application of self‐healing materials in ESDs according to their self‐healing chemistry, including hydrogen bonds, electrostatic interactions, and borate ester bonds, are described in detail. Based on these, critical challenges and important future directions of self‐healing ESDs are discussed.

Due to high ionic conductivity and low cost, Li1.4Al0.4Ti1.6(PO4)3 (LATP) has emerged as a promising solid‐state electrolyte for next‐generation lithium (Li) metal solid‐state batterie with high safety performance and energy density. However, the extremely high impedance and surface instability of LATP with Li metal retard its practical application. Herein, a novel method is proposed to construct an ultrathin ZnO layer that is tightly coated on the LATP pellets, surface (ZnO@LATP) via magnetron sputtering, which in situ reacts with Li to form a low electronic conductivity and multifunctional solid electrolyte interphase (SEI). The formed SEI can not only effectively lower the interfacial resistance, but also overcome the side reactions of LATP with the Li metal anode and suppress the Li dendrite growth. Specifically, the interface resistance decreases from 80 554 to 353 Ω and the overpotential reduces from 1 V to 20 mV. As a result, the Li/ZnO@LATP@ZnO/Li symmetric batteries can stably cycle for more than 2000 h without short circuit at 0.05 mA cm−2 and Li/ZnO@LATP/LiFePO4 batteries show excellent cycle stability for 200 cycles at 0.1 C. This work highlights the significance of multifunctional interphase between LATP and Li metal for improvement of interfacial impedance and instability.

Stabilizing high-voltage LCO cycling is a hot topic in both academic and industrial research. [3,4] However, the exact mechanism that caused the quick fading of high-voltage LCO has not yet reached consensus. [5,6] The band energy diagram in Figure S1 in the Supporting Information shows that cycling LCO to high voltage must entail a hybrid O anion (O 2− →O α− , α < 2) and Co cation-redox (HACR). [7,8] It is tempting to "exploit" HACR in LCO for much higher capacity, e.g., if LCO is charged to above 4.6 V, more than 220 mAh g −1 can be obtained; however, because of the reduced ionic radius and electrostatic force, the oxidized O α− would become much mobile [9] and more likely to escape from the particle, resulting in oxygen loss (OL). Continuous OL can be a killer problem to high-voltage cycling. [10] First, OL causes irreversible phase transformations (CoO 2 →Co 3 O 4) [11] (Figure S2, Supporting As the pioneer cathode for rechargeable Li-ion battery, [1] LiCoO 2 (LCO) is still dominating today's battery markets in consumer electronic devices, due to its high volumetric energy density and stable cycling. However, as LCO is only cycled within 4.35 V and 165 mAh g −1 at the present to meet the industrial-level cycling life, [2] there is still a large space to increase its utilizable capacity by charging LCO to higher voltages before it reaches

Sodium metal batteries have potentially high energy densities, but severe sodium-dendrite growth and side reactions prevent their practical applications, especially at high temperatures. Herein, we design an inorganic ionic conductor/gel polymer electrolyte composite, where uniformly cross-linked beta alumina nanowires are compactly coated by a poly(vinylidene fluoride-co-hexafluoropropylene)-based gel polymer electrolyte through their strong molecular interactions. These  beta alumina nanowires combined with the gel polymer layer create dense and homogeneous solid-liquid hybrid sodium-ion transportation channels through and along the nanowires, which promote uniform sodium deposition and formation of a stable and flat solid electrolyte interface on the sodium metal anode. Side reactions between the sodium metal and liquid electrolyte, as well as sodium dendrite formation, are successfully suppressed, especially at 60 °C. The sodium vanadium phosphate/sodium full cells with composite electrolyte exhibit 95.3% and 78.8% capacity retention after 1000 cycles at 1 C at 25 °C and 60 °C, respectively.

A synergetic strategy with ex situ anodic pretreatment and in-built GPEs enables safe and high energy QSLMBs.