Li‐rich manganese based oxides (LRMOs) are considered an attractive high‐capacity cathode for advanced Li‐ion batteries; however, their poor cyclability and gradual voltage fading have hindered their ...practical applications. Herein, an efficient and facile strategy is proposed to stabilize the lattice structure of LRMOs by surface modification of polyacrylic acid (PAA). The PAA‐coated LRMO electrode exhibits only 104 mV of the voltage fading after 100 cycles and 88% capacity retention over 500 cycles. The structural stability is attributed to the carboxyl groups in PAA chains reacting with oxygen species on the surface of LRMO to form a uniform and tightly coated film, which significantly suppresses the dissolution of transition metal elements from the cathode materials into the electrolyte. Importantly, a H+/Li+ exchange reaction takes place between the LRMO and PAA, generating a proton‐doped surface layer. Density functional theory calculations and experimental evidence demonstrates that the H+ ions in the surface lattice efficiently inhibit the migration of transition metal ions, leading to a stabilized lattice structure. This surface modification approach may provide a new route to building a stable Li‐rich oxide cathode with high capacity retention and low voltage fading for practical Li‐ion battery applications.
Voltage fading of a Li‐rich oxide cathode is efficiently suppressed by using a polyacrylic acid (PAA) binder to build a well‐protected and partially‐protonated surface. The PAA‐coated Li‐rich manganese‐based oxides electrode exhibits only 104 mV of voltage fading after 100 cycles and 88% capacity retention over 500 cycles.
Hard carbon has been regarded as the most promising anode material for sodium‐ion batteries (SIBs) due to its low cost, high reversible capacity, and low working potential. However, the uncertain ...sodium storage mechanism hinders the rational design and synthesis of high‐performance hard carbon anode materials for practical SIBs. During the past decades, tremendous efforts have been put to stimulate the development of hard carbon materials. In this review, we discuss the recent progress of the study on the sodium storage mechanism of hard carbon anodes, and the effective strategies to improve their sodium storage performance have been summarized. It is anticipated that hard carbon anodes with high electrochemical properties will be inspired and fabricated for large‐scale energy storage applications.
Hard carbon electrode materials have been considered as a state‐of‐the‐art anode material for sodium‐ion batteries. However, the uncertain sodium storage mechanism hinders the development of high‐performance hard carbon anode materials for practical application. Herein, the progress in the sodium storage mechanism of hard carbon anodes and the effective strategies to improve their sodium storage performance are summarized. It is anticipated that this article will facilitate a better understanding of the development of hard carbon anode materials.
As promising cathode materials, iron‐based phosphate compounds have attracted wide attention for sodium‐ion batteries due to their low cost and safety. Among them, sodium iron fluorophosphate ...(Na2FePO4F) is widely noted due to its layered structure and high operating voltage compared with NaFePO4. Here, a mesoporous Na2FePO4F@C (M‐NFPF@C) composite derived from mesoporous FePO4 is synthesized through a facile ball‐milling combined calcination method. Benefiting from the mesoporous structure and highly conductive carbon, the M‐NFPF@C material exhibits a high reversible capacity of 114 mAh g−1 at 0.1 C, excellent rate capability (42 mAh g−1 at 10 C), and good cycling performance (55% retention after 600 cycles at 5 C). The high plateau capacity obtained (>90% of total capacity) not only shows high electrochemical reversibility of the as‐prepared M‐NFPF@C but also provides high energy density, which mainly originates from its mesoporous structure derived from the mesoporous FePO4 precursor. The M‐NFPF@C serves as a promising cathode material with high performance and low cost for sodium‐ion batteries.
A mesoporous Na2FePO4F@C (M‐NFPF@C) composite derived from mesoporous FePO4 is synthesized through a facile ball‐milling combined calcination method. Benefiting from the mesoporous structure and highly conductive carbon, the M‐NFPF@C material exhibits a high reversible capacity of 114 mAh g−1 at 0.1 C, excellent rate capability (42 mAh g−1 at 10 C), and good cycling performance (55% retention after 600 cycles at 5 C).
Iron sulfides with high theoretical capacity and low cost have attracted extensive attention as anode materials for sodium ion batteries. However, the inferior electrical conductivity and devastating ...volume change and interface instability have largely hindered their practical electrochemical properties. Here, ultrathin amorphous TiO2 layer is constructed on the surface of a metal–organic framework derived porous Fe7S8/C electrode via a facile atomic layer deposition strategy. By virtue of the porous structure and enhanced conductivity of the Fe7S8/C, the electroactive TiO2 layer is expected to effectively improve the electrode interface stability and structure integrity of the electrode. As a result, the TiO2‐modified Fe7S8/C anode exhibits significant performance improvement for sodium‐ion batteries. The optimal TiO2‐modified Fe7S8/C electrode delivers reversible capacity of 423.3 mA h g−1 after 200 cycles with high capacity retention of 75.3% at 0.2 C. Meanwhile, the TiO2 coating is conducive to construct favorable solid electrolyte interphase, leading to much enhanced initial Coulombic efficiency from 66.9% to 72.3%. The remarkable improvement suggests that the interphase modification holds great promise for high‐performance metal sulfide‐based anode materials for sodium‐ion batteries.
Ultrathin amorphous TiO2 layer is directly constructed on the surface of Fe7S8/C electrode by facile atomic layer deposition strategy. Benefiting from TiO2 surface modification, the Fe7S8@C electrode exhibits much improved sodium storage performance (423.3 mA h g−1 after 200 cycles at 0.2 C with high capacity retention of 75.3% and enhanced initial coulombic efficiency of 72%).
Dual‐carbon batteries (DCBs) are a promising candidate for smart grid applications, owing to their low cost, high power capability, and environmentally friendly benefits. As an essential component of ...DCBs, electrolytes not only act as a medium for ion migration during the running of the battery, but also provide active ions to be intercalated into carbon electrodes, exerting significant impacts on the electrochemical performance and safety of the DCB. In this Review, we discuss recent progress in electrolyte research for DCBs, including conventional liquid electrolytes, highly concentrated electrolytes, and gel polymer electrolytes, with a focus on their stability and compatibility with carbon electrodes. Finally, we present perspectives on the current limitations and future research directions of electrolytes for DCBs. Some recommendations for battery evaluation are also offered.
Time to dual: Recent progress in dual‐carbon battery electrolytes are comprehensively reviewed with a focus on their stability and compatibility with carbon electrodes. The Review also presents perspectives on the current limitations and future research directions of electrolytes for dual‐carbon batteries.
Many renewable energy technologies, especially batteries and supercapacitors, require effective electrode materials for energy storage and conversion. For such applications, metal‐organic frameworks ...(MOFs) and covalent‐organic frameworks (COFs) have been recently emerged as promising candidates. Their high surface area, organized channel, and multiple functions make them highly versatile and flexible as electrodes, electrolytes, and electrocatalysts in electrochemical energy storage (EES) systems. In addition, many MOFs/COFs‐derived materials tend to possess high conductivity and diverse nanoarchitecture, and can also serve as high‐performance electrodes. In this review, we summarize the extensive potentials of both frameworks and their derivatives in a range of devices, including lithium/sodium ion, lithium‐sulfur, lithium‐oxygen batteries, and supercapacitors. In addition, we discuss the remaining challenges in this area and propose potential solutions for them as well as outline a few possible directions for further development for EES applications.
Metal/covalent organic frameworks (MOFs/COFs) have received wide attention for electrochemical energy storage (EES) due to their unique structural characteristics. Herein, we summarize the applications of MOFs/COFs and their derivatives in EES, including lithium/sodium ion, lithium‐sulfur, lithium‐oxygen batteries, and supercapacitors. Moreover, the development perspective of MOFs/COFs in EES is also outlined.
As a promising cathode material, Na3V2(PO4)2F3 (NVPF) has attracted wide attention for sodium-ion batteries (SIBs) because of its high operating voltage and high structural stability. However, the ...low intrinsic electronic conductivity and insufficient Na ion mobility of NVPF limit its development. Herein, K-doping NVPF is prepared through a facile ball-milling combined calcination method. The effects of K-doping on the crystal structure, kinetic properties and electrochemical performance are investigated. The results demonstrate that the Na2.90K0.10V2(PO4)3F3 (K0.10-NVPF) exhibits a high capacity (120.8 mAh g−1 at 0.1 C), high rate capability (66 mAh g−1 at 30 C) and excellent cycling performance (a capacity retention of 97.5% at 1 C over 500 cycles). Also, the occupation site of K ions in the lattice, electronic band structure and Na-ion transport kinetic property in K-doped NVPF are investigated by density functional theory (DFT) calculations, which reveals that the K-doped NVPF exhibits improved electronic and ionic conductivities, and located K+ ions in the lattice to contribute to high reversible capacity, rate capability and cycling stability. Therefore, the K-doped NVPF serves as a promising cathode material for high-energy and high-power SIBs.
A novel cathode, K doped Na3V2(PO4)2F3 is synthesized by a facile ball-milling method. With the structural advantages and the suitable K doping site, the K-doped Na3V2(PO4)2F3 cathode exhibits enhanced sodium storage performance in terms of high specific capacity, excellent rate capability, and superior cycling stability. Display omitted
To understand Baduanjin rehabilitation therapy in mild COVID-19 patients.
A narrative review.
A literature search for COVID-19 and Baduanjin treatments was conducted on Chinese and English electronic ...databases: China National Knowledge Infrastructure, Wanfang Data, Embase, PubMed, Scopus, Science Direct, Ebscohost, SPORTDiscus and ProQuest.
Twelve studies on the Baduanjin rehabilitation for COVID-19 patients have been included. We acknowledged the considerable published research and current clinical practice using Baduanjin for COVID-19 treatment in the following areas: anxiety, depression, insomnia, lung function rehabilitation, immunity and activity endurance.
The use of Baduanjin as adjuvant therapy for COVID-19 patients' rehabilitation is still limited, therefore, more clinical studies are needed to confirm its efficacy.
Hard carbons (HC) have potential high capacities and power capability, prospectively serving as an alternative anode material for Li‐ion batteries (LIB). However, their low initial coulombic ...efficiency (ICE) and the resulting poor cyclability hinder their practical applications. Herein, a facile and effective approach is developed to prelithiate hard carbons by a spontaneous chemical reaction with lithium naphthalenide (Li‐Naph). Due to the mild reactivity and strong lithiation ability of Li‐Naph, HC anode can be prelithiated rapidly in a few minutes and controllably to a desirable level by tuning the reaction time. The as‐formed prelithiated hard carbon (pHC) has a thinner, denser, and more robust solid electrolyte interface layer consisting of uniformly distributed LiF, thus demonstrating a very high ICE, high power, and stable cyclability. When paired with the current commercial LiCoO2 and LiFePO4 cathodes, the assembled pHC/LiCoO2 and pHC/LiFePO4 full cells exhibit a high ICE of >95.0% and a nearly 100% utilization of electrode‐active materials, confirming a practical application of pHC for a new generation of high capacity and high power LIBs.
A facile chemical prelithiation approach is developed to eliminate the irreversible capacity loss of hard carbon (HC) anode via a spontaneous chemical reaction with lithium naphthalenide reagent. When paired with LiCoO2 cathode, the HC/LiCoO2 full cell demonstrates a high initial coulombic efficiency of >95.0%, confirming a practical application for high energy and high power Li‐ion batteries.
Sodium-ion batteries(SIBs) are promising for grid-scale energy storage applications due to the natural abundance and low cost of sodium. Among various Na insertion cathode materials, Na
0.44
MnO
2
...has attracted the most attention because of its cost effectiveness and structural stability. However, the low initial charge capacity for Na-poor Na
0.44
MnO
2
hinders its practical applications. Herein, we developed a facile chemical presodiated method using sodiated biphenly to transform Na-poor Na
0.44
MnO
2
into Na-rich Na
0.66
MnO
2
. After presodiation, the initial charge capacity of Na
0.44
MnO
2
is greatly enhanced from 56.5 mA·h/g to 115.7 mA·h/g at 0.1 C(1 C=121 mA/g) and the excellent cycling stability(the capacity retention of 94.1% over 200 cycles at 2 C) is achieved. This presodiation strategy would open a new avenue for promoting the practical applications of Na-poor cathode materials in sodium-ion batteries.
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