A Fast-Charging and High-Temperature All-Organic Rechargeable Potassium Battery.

Developing fast-charging, high-temperature, and sustainable batteries is critical for the large-scale deployment of energy storage devices in electric vehicles, grid-scale electrical energy storage, and high temperature regions. Here, a transition metal-free all-organic rechargeable potassium battery (RPB) based on abundant and sustainable organic electrode materials (OEMs) and potassium resources for fast-charging and high-temperature applications is demonstrated. N-doped graphene and a 2.8 m potassium hexafluorophosphate (KPF6 ) in diethylene glycol dimethyl ether (DEGDME) electrolyte are employed to mitigate the dissolution of OEMs, enhance the electrode conductivity, accommodate large volume change, and form stable solid electrolyte interphase in the all-organic RPB. At room temperature, the RPB delivers a high specific capacity of 188.1 mAh g-1 at 50 mA g-1 and superior cycle life of 6000 and 50000 cycles at 1 and 5 A g-1 , respectively, demonstrating an ultra-stable and fast-charging all-organic battery. The impressive performance at room temperature is extended to high temperatures, where the high-mass-loading (6.5 mg cm-2 ) all-organic RPB exhibits high-rate capability up to 2 A g-1 and a long lifetime of 500 cycles at 70-100 °C, demonstrating a superb fast-charging and high-temperature battery. The cell configuration demonstrated in this work shows great promise for practical applications of sustainable batteries at extreme conditions.

Halogenated Carboxylates as Organic Anodes for Stable and Sustainable Sodium-Ion Batteries.

Organic materials are competitive as anodes for Na-ion batteries (NIBs) due to the low cost, abundance, environmental benignity, and high sustainability. Herein, we synthesized three halogenated carboxylate-based organic anode materials to exploit the impact of halogen atoms (F, Cl, and Br) on the electrochemical performance of carboxylate anodes in NIBs. The fluorinated carboxylate anode, disodium 2, 5-difluoroterephthalate (DFTP-Na), outperforms the other carboxylate anodes with H, Cl, and Br, in terms of high specific capacity (212 mA h g-1), long cycle life (300 cycles), and high rate capability (up to 5 A g-1). As evidenced by the experimental and computational results, the two F atoms in DFTP reduce the solubility, enhance the cyclic stability, and interact with Na+ during the redox reaction, resulting in a high-capacity and stable organic anode material in NIBs. Therefore, this work proves that fluorinating carboxylate compounds is an effective approach to developing high-performance organic anodes for stable and sustainable NIBs.

Compacted N-Doped 3D Bicontinuous Nanoporous Graphene/Carbon Nanotubes@Ni-Doped MnO2 Electrode for Ultrahigh Volumetric Performance All-Solid-State Supercapacitors at Wide Temperature Range.

Developing wide temperature range flexible solid-state supercapacitors with high volumetric energy density is highly desirable to meet the demands of the rapidly developing field of miniature consumer electronic devices and promote their widespread adoption. Herein, high-quality dense N-doped 3D porous graphene/carbon nanotube (N-3DG/CNTs) hybrid films are prepared and used as the substrate for the growth of Ni-doped MnO2 (Ni-MnO2 ). The integrated and interconnected architecture endows N-3DG/CNTs@Ni-MnO2 composite electrodes' high conductivity and fast ion/electron transport pathway. Subsequently, 2.4 V solid-state supercapacitors are fabricated based on compacted N-3DG/CNTs@Ni-MnO2 positive electrodes, which exhibit an ultrahigh volumetric energy density of 78.88 mWh cm-3 based on the entire device including electrodes, solid-state electrolyte, and packing films, excellent cycling stability up to 10 000 cycles, and a wide operating temperature range from -20 to 70 °C. This work demonstrates a design of flexible solid-state supercapacitors with exceptional volumetric performance capable of operation under extreme conditions.

A conjugated tetracarboxylate anode for stable and sustainable Na-ion batteries.

A conjugated tetracarboxylate, 1,2,4,5-benzenetetracarboxylate sodium salt (Na4C10H2O8), was designed and synthesized as an anode material in Na-ion batteries (NIBs). This organic compound shows low redox potentials (∼0.65 V), long cycle life (1000 cycles), and fast charging capability (up to 2 A g-1), demonstrating a promising organic anode for stable and sustainable NIBs.

A Powder Metallurgic Approach toward High-Performance Lithium Metal Anodes.

The development of lithium metal anodes capable of sustaining large volume changes, avoiding lithium dendrite formation, and remaining stable in ambient air is crucial for commercially viable lithium metal batteries. Toward this goal, the fabrication of porous and lithiophilic copper scaffolds via a powder metallurgy strategy is reported. Infiltrating the scaffolds with molten lithium followed by exposure to Freon R134a produces lithium metal anodes with dramatically improved rate performance and cycling stability. This work provides a simple yet effective route for the fabrication of safe, low-cost lithium metal batteries with high energy density.

Octopus-Inspired Design of Apical NiS2 Nanoparticles Supported on Hierarchical Carbon Composites as an Efficient Host for Lithium Sulfur Batteries with High Sulfur Loading.

Developing high-performance Li-S batteries with high sulfur loading is highly desirable for practical application and remains a major challenge. To achieve this goal, the following requirements for designing carbon/metal compound composites need to be met: (i) the carbon materials need to exhibit suitable specific surface area, void structure, and electrical conductivity; (ii) the weight content of the metal compounds should be low; and (iii) the metal compounds need to show a strong adsorption and efficient electrocatalytic function for LiPSs. In this study, inspired by the body structure of an octopus, a new carbon/NiS2 hierarchical composite is reported, in which the apical NiS2 nanoparticles (0D) on a 1D carbon nanotubes (CNTs) are supported on a three-dimensional carbon (3DC) framework (3DC-CNTs-NiS2). The 3DC-CNTs-NiS2 composite has a high specific surface area (271 m2 g-1), good electrical conductivity, and low NiS2 content (9.2 wt %), and the apical NiS2 nanoparticles are capable of adsorption and electrocatalysis toward LiPSs, demonstrated by both electrochemical characterization and theoretical calculation. When used as a cathode host of the Li-S battery, it exhibits an ultra-stable cycling performance with a fade rate of 0.043% per cycle over 1000 cycles; even with a high S loading (6.5 mg cm-2 with 90 wt % of S), the soft package battery delivers a high area capacity of 5.0 mAh cm-2 under the E/S ratio of 5 µLE mg-1s. This work provides a new approach to design and fabricate multi-functional S hosts with high S loading.

N-Doped Porous Carbon Nanofibers/Porous Silver Network Hybrid for High-Rate Supercapacitor Electrode.

A three-dimensional cross-linked porous silver network (PSN) is fabricated by silver mirror reaction using polymer foam as the template. The N-doped porous carbon nanofibers (N-PCNFs) are further prepared on PSN by chemical vapor deposition and treated by ammonia gas subsequently. The PSN substrate serving as the inner current collector will improve the electron transport efficiency significantly. The ammonia gas can not only introduce nitrogen doping into PCNFs but also increase the specific surface area of PCNFs at the same time. Because of its large surface area (801 m2/g), high electrical conductivity (211 S/cm), and robust structure, the as-constructed N-PCNFs/PSN demonstrates a specific capacitance of 222 F/g at the current density of 100 A/g with a superior rate capability of 90.8% of its initial capacitance ranging from 1 to 100 A/g while applied as the supercapacitor electrode. The symmetric supercapacitor device based on N-PCNFs/PSN displays an energy density of 8.5 W h/kg with power density of 250 W/kg and excellent cycling stability, which attains 103% capacitance retention after 10 000 charge-discharge cycles at a high current density of 20 A/g, which indicates that N-PCNFs/PSN is a promising candidate for supercapacitor electrode materials.

Free-standing porous carbon nanofiber/ultrathin graphite hybrid for flexible solid-state supercapacitors.

A micrometer-thin solid-state supercapacitor (SC) was assembled using two pieces of porous carbon nanofibers/ultrathin graphite (pCNFs/G) hybrid films, which were one-step synthesized by chemical vapor deposition using copper foil supported Co catalyst. The continuously ultrathin graphite sheet (∼ 25 nm) is mechanically compliant to support the pCNFs even after etching the copper foil and thus can work as both current collector and support directly with nearly ignorable fraction in a SC stack. The pCNFs are seamlessly grown on the graphite sheet with an ohmic contact between the pCNFs and the graphite sheet. Thus, the accumulated electrons/ions can duly transport from the pCNFs to graphite (current collector), which results in a high rate performance. The maximum energy density and power density based on the whole device are up to 2.4 mWh cm(-3) and 23 W cm(-3), which are even orders higher than those of the most reported electric double-layer capacitors and pseudocapacitors. Moreover, the specific capacitance of the device has 96% retention after 5000 cycles and is nearly constant at various curvatures, suggesting its wide application potential in powering wearable/miniaturized electronics.