Highly Li‐ion conductive Li4(BH4)3I@SBA‐15 is synthesized by confining the LiI doped LiBH4 into mesoporous silica SBA‐15. Uniform nanoconfinement of P63 mc phase Li4(BH4)3I in SBA‐15 mesopores leads to a significantly enhanced conductivity of 2.5 × 10−4 S cm−1 with a Li‐ion transference number of 0.97 at 35 °C. The super Li‐ion mobility in the interface layer with a thickness of 1.2 nm between Li4(BH4)3I and SBA‐15 is believed to be responsible for the fast Li‐ion conduction in Li4(BH4)3I@SBA‐15. Additionally, Li4(BH4)3I@SBA‐15 also exhibits a wide apparent electrochemical stability window (0 to 5 V vs Li/Li+) and a superior Li dendrite suppression capability (critical current density 2.6 mA cm−2 at 55 °C) due to the formation of stable interphases. More importantly, Li4(BH4)3I@SBA‐15‐based Li batteries using either high‐capacity sulfur cathode or high‐voltage oxide cathode show excellent electrochemical performances, making Li4(BH4)3I@SBA‐15 a very attractive electrolyte for next‐generation all‐solid‐state Li batteries.

Li−B−H complexes facilely prepared via partial dehydrogenation of LiBH 4 are presented in this study as solid electrolytes for Li batteries. An exceptionally high Li-ion conductivity is found for the Li−B−H complex with 7.5 wt % H 2 desorption under 3 bar H 2 pressure, which reaches 2.7 × 10 −4 S cm −1 at 35 °C, more than 4 orders higher than that of LiBH 4 . In-depth characterizations show that LiH and [Li 2 B 12 H 11+1/n ] n are in situ formed in the LiBH 4 matrix and the interface layer between [Li 2 B 12 H 11+1/n ] n and LiBH 4 is believed to be responsible for the high Li-ion conductivity. Moreover, this Li−B−H complex also exhibits excellent electrochemical stability, which enables the stable cycling of all-solid-state batteries at room temperature.

Developing emerging materials for high energy‐density lithium–sulfur (Li–S) batteries is of great significance to suppress the shuttle effect of polysulfides and to accommodate the volumetric change of sulfur. Here, a novel porous microcapsule system containing a carbon nanotubes/tin dioxide quantum dots/S (CNTs/QDs/S) composite core and a porous shell prepared through a liquid‐driven coaxial microfluidic method as Li–S battery cathode is developed. The encapsulated CNTs in the microcapsules provide pathways for electron transport; SnO2 QDs on CNTs immobilize the polysulfides by strong adsorption, which is verified by using density functional theory calculations on binding energies. The porous shell of the microcapsule is beneficial for ion diffusion and electrolyte penetration. The void inside the microcapsule accommodates the volumetric change of sulfur. The Li–S battery based on the porous CNTs/QDs/S microcapsules displays a high capacity of 1025 mAh g−1 after 100 cycles at 0.1 C. When the sulfur loading is 2.03 mg cm−2, the battery shows a stable cycling life of 700 cycles, a Coulombic efficiency exceeding 99.9%, a recoverable rate‐performance during repeated tests, and a good temperature tolerance at both −5 and 45 °C, which indicates a potential for applications at different conditions.

Magnesium batteries have been considered promising candidates for next‐generation energy storage systems owing to their high energy density, good safety without dendrite formation, and low cost of magnesium resources. However, high‐performance cathodes with stable capacity, good conductivity, and fast ions transport are needed, since many conventional cathodes possess a low performance and poor preparation controllability. Herein, a liquid‐driven coaxial flow focusing (LDCFF) approach for preparing a novel microcapsule system with controllable size, high loading, and stable magnesium‐storage performance is presented. Taking the MoS2‐infilled microcapsule as a case study, the magnesium battery cathode based on the microcapsules displays a capacity of 100 mAh g−1 after 100 cycles. High capacity retention is achieved at both low and high temperatures of −10, ‒5, and 45 °C, and a stable rate‐performance is also obtained. The influences of the liquid flow rates on the size and shell thickness of the microcapsules are investigated; and electron and ion diffusion properties are also studied by first‐principle calculations. The presented LDCFF method is quite general, and the high performance of the microcapsules enables them to find broad applications for making emerging energy‐storage materials and secondary battery systems.

High-energy-density secondary batteries are required for many applications such as electric vehicles. Lithium-sulfur (Li-S) batteries are receiving broad attention because of their high theoretical energy density. However, the large volume change of sulfur during cycling, poor conductivity, and the shuttle effect of sulfides severely restrict the Li-storage performance of Li-S batteries. Herein, we present a novel core-shell nanocomposite consisting of a sulfur core and a hydrogel polypyrrole (PPy) shell, enabling an ultra-high sulfur content of about 98.4% within the composite, which greatly exceeds many other conventional composites obtained by coating sulfur onto some hosts. In addition, the void inside the core-shell structure effectively accommodates the volume change; the conductive PPy shell improves the conductivity of the composite; and PPy is able to adsorb polysulfides, suppressing the shuttle effect. After cycling for 200 cycles, the prepared S@void@PPy composite retains a stable capacity of 650 mAh g −1 , which is higher than the bare sulfur particles. The composite also exhibits a fast Li ion diffusion coefficient. Furthermore, the density functional theory calculations show the PPy shell is able to adsorb polysulfides efficiently, with a large adsorption energy and charge density transfer.