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Lead (Pb)–Tin (Sn) mixed perovskites suffer from large open-circuit voltage (Voc) loss due to the rapid crystallization of perovskite films, creating Sn and Pb vacancies. Such vacancies act as defe...

Solid-state lithium batteries are generally considered as the next-generation battery technology that benefits from inherent nonflammable solid electrolytes and safe harnessing of high-capacity lithium metal. Among various solid-electrolyte candidates, cubic garnet-type Li7La3Zr2O12 ceramics hold superiority due to their high ionic conductivity (10–3 to 10–4 S cm−1) and good chemical stability against lithium metal. However, practical deployment of solid-state batteries based on such garnet-type materials has been constrained by poor interfacing between lithium and garnet that displays high impedance and uneven current distribution. Herein, we propose a facile and effective strategy to significantly reduce this interfacial mismatch by modifying the surface of such garnet-type solid electrolyte with a thin layer of silicon nitride (Si3N4). This interfacial layer ensures an intimate contact with lithium due to its lithiophilic nature and formation of an intermediate lithium–metal alloy. The interfacial resistance experiences an exponential drop from 1197 to 84.5 Ω cm2. Lithium symmetrical cells with Si3N4-modified garnet exhibited low overpotential and long-term stable plating/stripping cycles at room temperature compared to bare garnet. Furthermore, a hybrid solid-state battery with Si3N4-modified garnet sandwiched between lithium metal anode and LiFePO4 cathode was demonstrated to operate with high cycling efficiency, excellent rate capability, and good electrochemical stability. This work represents a significant advancement toward use of garnet solid electrolytes in lithium metal batteries for the next-generation energy storage devices.

Electric double-layer capacitor (EDLC), as one type of supercapacitor, holds great promises for fast-charging energy storage devices but suffers from limited specific capacitance. The design and development of high performance EDLC-type carbon materials with the effective synergistic effect of high conductivity, tailored porous structure, and high surface area still remain challenging. Here, we report a novel hierarchical porous carbon with a combination of highly conductive electronic pathways and rich ionic storage units in three-dimensional network morphology, leading to high specific capacitance of EDLC. Specifically, by facile hydrothermal synthesis and carbonization, the carbon electrode derived from metal-organic framework and polymer fibers, exhibits extremely high specific capacitance of ∼ 385 F g−1 at 0.1 A g−1 and can still maintain capacitance of 303 F g−1 at 10 A g−1. The high electrochemical performance can be attributed to the rich network of micro and mesoporous structures for electrolyte transport and ion adsorption as well as highly conductive electronic pathways inside the electrodes. The assembled EDLC thus delivers a high energy density of 10.51 Wh kg−1 and a power density of 5.454 kW kg−1 at the current density of 10 A g−1 in the aqueous electrolyte. Hence, the present study is expected to open a promising route to developing porous materials for high-performance energy devices.

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries in large-scale energy storage due to the abundant sodium resources and low cost. However, the practical applications are still hindered by several factors such as limited cycling life and low mass loading of the electrode. Herein, a uniform free-standing Sn-based (Sn@CFC) electrode was synthesized via a facile electrospinning method. The cross-link nitrogen-doped carbon fiber and ultrasmall metallic Sn nanoparticles together provide fast ions and electrons pathway, enabling a dominant pseudocapacitance contribution of 87.1% at a scan rate of 0.5 mV s−1. The Sn@CFC electrode hence exhibits a high reversible area capacity of 1.68 mAh cm−2 at 50 mA g−1 and long cycle life of 1000 cycles at 200 mA g−1 with more than 80% capacity retention. Moreover, the facile manufacturing technique yields the Sn@CFC electrode with an extremely high mass loading of 5.5 mg cm−2 with very little sacrifice of electrochemical performances. This study provides a promising route to scalably fabricate electrodes with high area capacity and high energy density for advanced SIBs.