Bismuth–Antimony Alloy Nanoparticle@Porous Carbon Nanosheet Composite Anode for High-Performance Potassium-Ion Batteries

Antimony (Sb)-based anode materials have recently aroused great attention in potassium-ion batteries (KIBs), because of their high theoretical capacities and suitable potassium inserting potentials. Nevertheless, because of large volumetric expansion and severe pulverization during potassiation/depotassiation, the performance of Sb-based anode materials is poor in KIBs. Herein, a composite nanosheet with bismuth–antimony alloy nanoparticles embedded in a porous carbon matrix (BiSb@C) is fabricated by a facile freeze-drying and pyrolysis method. The introduction of carbon and bismuth effectively suppress the stress/strain originated from the volume change during charge/discharge process. Excellent electrochemical performance is achieved as a KIB anode, which delivers a high reversible capacity of 320 mA h g–1 after 600 cycles at 500 mA g–1. In addition, full KIBs by coupling with Prussian Blue cathode deliver a high capacity of 396 mA h g–1 and maintain 360 mA h g–1 after 70 cycles. Importantly, the operando X-ray diffraction investigation reveals a reversible potassiation/depotassiation reaction mechanism of (Bi,Sb) ↔ K­(Bi,Sb) ↔ K3(Bi,Sb) for the BiSb@C composite. Our findings not only propose a reasonable design of high-performance alloy-based anodes in KIBs but also promote the practical use of KIBs in large-scale energy storage

Molten Lithium-Filled Three-Dimensional Hollow Carbon Tube Mats for Stable Lithium Metal Anodes

Lithium (Li) metal is regarded as an ideal anode for the next-generation high-energy-density Li-ion batteries. However, its practical application has been seriously hindered by the dendrite growth and volume change during charge/discharge cycling. Herein, a three-dimensional (3D) hollow carbon tube (HCT) mat is fabricated from natural willow catkins to form HCT/Li composite through a scalable molten infusion method. The intrinsic heteroatoms endow the HCTs with excellent lithiophilicity, and molten Li can be impregnated into the 3D HCT mat easily via capillary driving force. As a result, a uniform Li plating/stripping and stable Li composite anode were demonstrated, delivering 500 stable cycles at 2 mA cm–2. Furthermore, a full cell using a commercial lithium iron phosphate cathode achieves excellent cycling stability above 250 cycles at a high rate of 5 C (1 C = 170 mAh g–1). This work sheds light on a facile and practical method to construct a stable Li metal anode for remarkable Li metal rechargeable batteries

Optimization of Molecular Structure and Electrode Architecture of Anthraquinone-Containing Polymer Cathode for High-Performance Lithium-Ion Batteries

Molecular structure and electrode architecture play very important roles in electrochemical performance of polymer electrode materials for lithium-ion batteries. Here, a series of anthraquinone-containing polymers with linear (with different molecular weights (MWs)) or cross-linked polymer structures were synthesized by (living) ring-opening metatheses (co)­polymerization method. The influences of the molecular structures and electrode preparation process on the architectures and electrochemical performance of polymer electrodes were systematically investigated. It was found that the low MW linear polymers suffer from severe dissolution and thus result in low initial capacity and poor cycling stability. Under optimized electrode preparation process, high MW linear polymers can be uniformly composited with conductive additives and binders and deliver stable cycling performance. Cross-linked polymer shows significantly reduced solubility but a severe aggregation problem, leading to very poor electrochemical performance. Our findings shed light on the molecular structure design and electrode preparation process of polymer electrode materials for high-performance rechargeable batteries

Room-Temperature Potassium–Sulfur Batteries Enabled by Microporous Carbon Stabilized Small-Molecule Sulfur Cathodes

Potassium–sulfur (K–S) batteries are a promising alternative to lithium ion batteries for large-area energy storage applications, owing to their high capacity and inexpensiveness, but they have been seldom investigated. Here we report room-temperature K–S batteries utilizing a microporous carbon-confined small-molecule sulfur composite cathode. The synergetic effects of the strong confinement of microporous carbon matrix and the small-molecule sulfur structure can effectually eliminate the formation of soluble polysulfides and ensure a reversible capacity of 1198.3 mA h g–1 and retain 72.5% after 150 cycles with a Coulombic efficiency of ∼97%. The potassium-storage mechanism was investigated by X-ray photoelectron spectroscopy analysis and theoretical calculations. The results suggest that K2S is the final potassiation product along with the reaction of 2K + S ↔ K2S, giving a theoretical capacity of 1675 mA h g–1. Our findings not only provide an effective strategy to fabricate high-performance room-temperature K–S batteries but also offer a basic comprehension of the potassium storage mechanism of sulfur cathode materials

Achieving Fast and Reversible Sulfur Redox by Proper Interaction of Electrolyte in Potassium Batteries

Potassium–sulfur batteries have potential for low-cost and high-energy density energy storage. However, it is a challenge to find suitable electrolytes affording liquid environment for intermediate sulfur species to convert at high voltages. In this study, a series of ether/potassium salt systems were systematically studied to investigate the electrochemical stability and function of the electrolytes in sulfur electrochemistry by using in situ ultraviolet–visible and Fourier-transform infrared spectroscopies. Interactions of soluble polysulfides with the electrolyte were critical to the electrochemical performance. Under optimized conditions, the bis(trifluoromethanesulfonyl)imide anion demonstrated moderate interaction and reversible solvation/desolvation of polysulfides. Polar carboxyl groups in poly(acrylic acid) were effective for binding polysulfide in electrodes, enabling reversible sulfur conversions at high working voltages and improved initial Coulombic efficiency. This enhanced battery performance was achieved even using a conventional carbon host with a high sulfur loading of ∼69 wt %, i.e., ∼49 wt % in the cathode

Room-Temperature Potassium–Sulfur Batteries Enabled by Microporous Carbon Stabilized Small-Molecule Sulfur Cathodes

Potassium–sulfur (K–S) batteries are a promising alternative to lithium ion batteries for large-area energy storage applications, owing to their high capacity and inexpensiveness, but they have been seldom investigated. Here we report room-temperature K–S batteries utilizing a microporous carbon-confined small-molecule sulfur composite cathode. The synergetic effects of the strong confinement of microporous carbon matrix and the small-molecule sulfur structure can effectually eliminate the formation of soluble polysulfides and ensure a reversible capacity of 1198.3 mA h g–1 and retain 72.5% after 150 cycles with a Coulombic efficiency of ∼97%. The potassium-storage mechanism was investigated by X-ray photoelectron spectroscopy analysis and theoretical calculations. The results suggest that K2S is the final potassiation product along with the reaction of 2K + S ↔ K2S, giving a theoretical capacity of 1675 mA h g–1. Our findings not only provide an effective strategy to fabricate high-performance room-temperature K–S batteries but also offer a basic comprehension of the potassium storage mechanism of sulfur cathode materials

Room-Temperature Potassium–Sulfur Batteries Enabled by Microporous Carbon Stabilized Small-Molecule Sulfur Cathodes

Potassium–sulfur (K–S) batteries are a promising alternative to lithium ion batteries for large-area energy storage applications, owing to their high capacity and inexpensiveness, but they have been seldom investigated. Here we report room-temperature K–S batteries utilizing a microporous carbon-confined small-molecule sulfur composite cathode. The synergetic effects of the strong confinement of microporous carbon matrix and the small-molecule sulfur structure can effectually eliminate the formation of soluble polysulfides and ensure a reversible capacity of 1198.3 mA h g–1 and retain 72.5% after 150 cycles with a Coulombic efficiency of ∼97%. The potassium-storage mechanism was investigated by X-ray photoelectron spectroscopy analysis and theoretical calculations. The results suggest that K2S is the final potassiation product along with the reaction of 2K + S ↔ K2S, giving a theoretical capacity of 1675 mA h g–1. Our findings not only provide an effective strategy to fabricate high-performance room-temperature K–S batteries but also offer a basic comprehension of the potassium storage mechanism of sulfur cathode materials

Ultrafast Synthesis of Layered Transition-Metal Oxide Cathodes from Metal–Organic Frameworks for High-Capacity Sodium-Ion Batteries

Layered transition-metal oxides are promising candidate cathode materials for sodium-ion batteries due to their abundant raw materials and high theoretical capacity. Nevertheless, a long-time high-temperature heat treatment is required in traditional preparation methods, leading to low synthesis efficiency and waste of energy. Herein, an ultrafast preparation method of layered transition-metal oxides was proposed through minute calcination of metal–organic frameworks (MOFs). The homogeneous distribution of different atoms in MOFs allows fast phase transition during the calcination process. P′2-phase layered sodium manganese oxide was successfully obtained and demonstrated excellent electrochemical performance, with a high reversible capacity of 212 mA h g–1 and a cycling performance of 84% capacity retention after 100 cycles. Furthermore, this method can be expanded to a wide variety of MOF precursors and oxide electrode materials for different types of batteries. Our findings provide an efficient and cost-effective synthesis method for high-performance layered transition-metal oxide cathodes

Self-Powered Disinfection Using Triboelectric, Conductive Wires of Metal–Organic Frameworks

Efficient water disinfection is vitally needed in rural and disaster-stricken areas lacking power supplies. However, conventional water disinfection methods strongly rely on external chemical input and reliable electricity. Herein, we present a self-powered water disinfection system using synergistic hydrogen peroxide (H2O2) assisted electroporation mechanisms driven by triboelectric nanogenerators (TENGs) that harvest electricity from the flow of water. The flow-driven TENG, assisted by power management systems, generates a controlled output with aimed voltages to drive a conductive metal–organic framework nanowire array for effective H2O2 generation and electroporation. The injured bacteria caused by electroporation can be further damaged by facile diffused H2O2 molecules at high throughput. A self-powered disinfection prototype enables complete disinfection (>99.9999% removal) over a wide range of flows up to 3.0 × 104 L/(m2 h) with low water flow thresholds (200 mL/min; ∼20 rpm). This rapid, self-powered water disinfection method is promising for pathogen control

Adaptive Ionization-Induced Tunable Electric Double Layer for Practical Zn Metal Batteries over Wide pH and Temperature Ranges

The violent side reactions of Zn metal in aqueous electrolyte lead to sharp local-pH fluctuations at the interface, which accelerate Zn anode breakdown; thus, the development of an optimization strategy to accommodate a wide pH range is particularly critical for improving aqueous Zn metal batteries. Herein, we report a pH-adaptive electric double layer (EDL) tuned by glycine (Gly) additive with pH-dependent ionization, which exhibits excellent capability to stabilize Zn anodes in wide-pH aqueous electrolytes. It is discovered that a Gly-ionic EDL facilitates the directed migration of charge carriers in both mildly acidic and alkaline electrolytes, leading to the successful suppression of local saturation. It is worth mentioning that the regulation effect of the additive concentration on the inner Helmholtz plane (IHP) structure of Zn electrodes is clarified in depth. It is revealed that the Gly additives without dimerization can develop orderly and dense vertical adsorption within the IHP to effectively reduce the EDL repulsive force of Zn2+ and isolate H2O from the anode surface. Consequently, they Zn anode with tunable EDL exhibits superior electrochemical performance in a wide range of pH and temperature, involving the prodigious cycle reversibility of 7000 h at Zn symmetric cells with ZnSO4-Gly electrolytes and an extended lifespan of 50 times in Zn symmetric cells with KOH-Gly electrolytes. Moreover, acidic Zn powder||MnO2 pouch cells, and alkaline high-voltage Zn||Ni0.8Co0.1Mn0.1O2 cells, and Zn||NiCo-LDH cells also deliver excellent cycling reversibility. The tunable EDL enables the ultrahigh depth of discharge (DOD) of 93%. This work elucidates the design of electrolyte additives compatible in a wide range of pH and temperature, which might cause inspiration in the fields of practical multiapplication scenarios for Zn anodes