Polymer‐based electrolytes have attracted ever‐increasing attention for all‐solid‐state lithium (Li) metal batteries due to their ionic conductivity, flexibility, and easy assembling into batteries, and are expected to overcome safety issues by replacing flammable liquid electrolytes. However, it is still a critical challenge to effectively block Li dendrite growth and improve the long‐term cycling stability of all‐solid‐state batteries with polymer electrolytes. Here, the interface between novel poly(vinylidene difluoride) (PVDF)‐based solid electrolytes and the Li anode is explored via systematical experiments in combination with first‐principles calculations, and it is found that an in situ formed nanoscale interface layer with a stable and uniform mosaic structure can suppress Li dendrite growth. Unlike the typical short‐circuiting that often occurs in most studied poly(ethylene oxide) systems, this interface layer in the PVDF‐based system causes an open‐circuiting feature at high current density and thus avoids the risk of over‐current. The effective self‐suppression of the Li dendrite observed in the PVDF–LiN(SO2F)2 (LiFSI) system enables over 2000 h cycling of repeated Li plating–stripping at 0.1 mA cm−2 and excellent cycling performance in an all‐solid‐state LiCoO2||Li cell with almost no capacity fade after 200 cycles at 0.15 mA cm−2 at 25 °C. These findings will promote the development of safe all‐solid‐state Li metal batteries.

Necklace-like N-doped hollow carbon with hierarchical pores was utilized as a free-standing high-performance potassium-ion storage anode.

Carbon nanomaterials show potential in achieving good potassium ion storage; however, the limited interlayer spacing in existing carbon nanomaterials greatly impacts the performance of potassium ion batteries (PIBs). Herein, we report a class of three-dimensional (3D) porous carbon framework materials constructed by S/N co-doping graphene nanosheets (CFM-SNG) with an ultralarge interlayer spacing (0.448 nm) and a rich edge defect as high-performance PIBs anodes. The resulting 3D CFM-SNG material achieves enhanced reversible capacity (348.2 mAh/g at 50 mA/g), cycling performance (188.8 mAh/g at 1000 mA/g after 2000 cycles), and rate capability (204.3 mAh/g at a high current density of 2000 mA/g). Density functional theory calculations further demonstrate that the S/N co-doping and formed edge defects not only favor the interlayer spacing expansion and the adsorption of K+ to the 3D CFM-SNG anode but also prevent variation in volume during the potassiation/depotassiation process.

The renewable energy sources with intermittent nature call for fast development of electrical energy storage (EES) devices for practical applications. [1] Over the past decades, lithium-ion batteries (LIBs) have pervaded our daily lives, ranging from portable electronics to large-scale EES systems. [2] However, the cost of rare lithium resources involving electrical grid and large-scale storage purposes have raised widespread concerns. In this regard, sodium-ion batteries (SIBs) are highly promising to meet these demands due to that sodium is practically inexhaustible and easily accessible around the globe. [3] However, the higher standard electrochemical potential of Na + /Na (−2.71 V versus SHE) than that of Li + / Li (−3.04 versus SHE) and the larger ion radius of Na + compared with Li + (1.02 Å versus 0.76 Å) mean that SIBs possess a lower energy density, and most conventional electrode materials of LIBs are not suitable for SIBs. Hence, it is of great significance to explore advanced electrode materials that could provide satisfactory specific capacities and rapid ion diffusion kinetics. So far, the development of the cathode materials for SIBs has progressed rapidly, including layered oxides [4] and polyanionic compounds. [5] As for the anodes, although hard carbon as a hotspot has been widely studied due to its high capacity and lower voltage platform, [6] the random adsorption sites and irregular channels for Na + migration lead to a relatively poor sodium-ion diffusion. 2D transition metal chalcogenides (TMCs) have been broadly reported as a kind of promising electrode materials for both LIBs and SIBs due to their open framework and unique electrochemical properties. [7,8] Among them, WS 2 as a typical 2D TMCs has a much larger interlayer spacing of 0.62 nm and weaker van der Waals interaction, which enables fast reversible Na + diffusion and avoids terrible volume expansion during Na + intercalation/deintercalation processes. [9] However, the terrible issue of pure WS 2 anode applied in SIBs is its low intrinsic electronic conductivity, significantly limiting the specific capacity, and rate performance. [10] Generally, the electrochemical properties of materials are strongly dependent on the conductivity of electrode materials as well as the diffusion rate of Na +. Thus, the scrupulous design and rational controllable synthesis of Engineering novel electrode materials with unique architectures has a significant impact on tuning the structural/electrochemical properties for boosting the performance of secondary battery systems. Herein, starting from well-organized WS 2 nanorods, an ingenious design of a one-step method is proposed to prepare a bimetallic sulfide composite with a coaxial carbon coating layer, simply enabled by ZIF-8 introduction. Rich sulfur vacancies and WS 2 /ZnS heterojunctions can be simultaneously developed, that significantly improve ionic and electronic diffusion kinetics. In addition, a homogeneous carbon protective layer around the surface of the composite guarantees an outstandi...

Thermal safety is one of the major issues for lithium‐ion batteries (LIBs) used in electric vehicles. The thermal runaway mechanism and process of LIBs have been extensively studied, but the thermal problems of LIBs remain intractable due to the flammability, volatility and corrosiveness of organic liquid electrolytes. To ultimately solve the thermal problem, all‐solid‐state LIBs (ASSLIBs) are considered to be the most promising technology. However, research on the thermal stability of solid‐state electrolytes (SEs) is still in its initial stage, and the thermal safety of ASSLIBs still needs further validation. Moreover, the specified reviews summarizing the thermal stability of ASSLIBs and all types of SEs are still missing. To fill this gap, this review systematically discussed recent progress in the field of thermal properties investigation for ASSLIBs, form levels of materials and interface to the whole battery. The thermal properties of three major types of SEs, including polymer, oxide, and sulfide SEs are systematically reviewed here. This review aims to provide a comprehensive understanding of the thermal stability of SEs for the benign development of ASSLIBs and their promising application under practical operating conditions.