A hierarchical host microstructure enables regulated inner Li deposition for stable Li metal electrodes

Dendritic lithium (Li) deposition is a critical issue hindering the development of next-generation high-energy-density Li metal batteries (LMBs). Confining Li deposition within a three-dimensional host is a general strategy to suppress the volume expansion of the Li electrode. However, precise control of continuous Li growth in the pore space of the host is rarely investigated, which is a crucial issue to enable a high utilization ratio of the hosted Li for practical LMBs. Herein, a novel hierarchical host structure possessing a multifunctional secondary porous structure to regulate the continuous Li growth with high uniformity and reversibility is proposed. The secondary porous structure consisting of carbon nanotubes, nickel and Li2O-enriched solid electrolyte interphase is in-situ generated via lithiation reaction of a modified nickel foam scaffold, exhibiting high lithiophilicity, fast Li+ transportation and charge transfer. The LMB utilizing Li metal electrodes hosted by this rational structure achieved a stable cycling over 300 cycles with a practical LiFePO4 positive electrode (~2.5 mAh cm-2) at 0.5C/0.5C in the voltage window of 2.5-4.4 V. This work provides a novel approach to designing the host microstructure for constructing more stable Li metal electrode in practical LMBs

NiS Nanorods as Cathode Materials for All-Solid-State Lithium Batteries with Excellent Rate Capability and Cycling Stability

Rate capability and cycling stability are the great challenges of all-solid-state lithium batteries, owing to the low lithium ion transfer kinetics in solid materials and poor interfacial compatibility between electrodes and electrolytes. In this work, one-dimensional nanostructured NiS and lithium metal are firstly employed in Li/70% Li2S-29% P2O5-1% P2O5/Li10GeP2S12/NiS all-solid-state lithium batteries, exhibiting excellent rate capability and cycling stability. NiS nanorods, with a diameter of 20-50 nm and length of 2-3 mu m, are prepared in a controllable manner by using a solvothermal method. Electrochemical performance measurements show that the reversible discharge ca-pacities of NiS nanorod electrodes can be as high as 670, 401, and 299 mAhg(-1) at the current densities of 100, 250, and 500 mAg(-1), respectively. Also, it displays excellent cycling stability, showing reversible discharge capacities up to 338 and 243 mAhg(-1) after 100 cycles at current densities of 250 and 500 mAg(-1), respectively. The electrochemical reaction mechanism of the NiS nanorods in all-solid-state lithium batteries is revealed by combining cyclic voltammetry and ex situ XRD measurements in detail, showing a reversible conversion reaction that is almost identical with that in the traditional lithium-ion batteries that utilize liquid electrolytes

Lithium/Sulfide All-Solid-State Batteries using Sulfide Electrolytes

All-solid-state lithium batteries (ASSLBs) are considered as the next generation electrochemical energy storage devices because of their high safety and energy density, simple packaging, and wide operable temperature range. The critical component in ASSLBs is the solid-state electrolyte. Among all solid-state electrolytes, the sulfide electrolytes have the highest ionic conductivity and favorable interface compatibility with sulfur-based cathodes. The ionic conductivity of sulfide electrolytes is comparable with or even higher than that of the commercial organic liquid electrolytes. However, several critical challenges for sulfide electrolytes still remain to be solved, including their narrow electrochemical stability window, the unstable interface between the electrolyte and the electrodes, as well as lithium dendrite formation in the electrolytes. Herein, the emerging sulfide electrolytes and preparation methods are reviewed. In particular, the required properties of the sulfide electrolytes, such as the electrochemical stabilities of the electrolytes and the compatible electrode/electrolyte interfaces are highlighted. The opportunities for sulfide-based ASSLBs are also discussed

Constructing stable lithium metal anodes using a lithium adsorbent with a high Mn3+/Mn4+ ratio

Lithium (Li) metal batteries (LMBs) have emerged as the most prospective candidates for post-Li-ion batteries. However, the practical deployment of LMBs is frustrated by the notorious Li dendrite growth on hostless Li metal anodes. Herein, a protonated Li manganese (Mn) oxide with a high Mn3+/Mn4+ ratio is used as a Li adsorbent for constructing highly stable Li metal anodes. In addition to the Mn3+ sites with high Li affinity that afford an ultralow Li nucleation overpotential, the decrease in the average Mnn+ oxidation state also induces a disordered adsorbent structure via the Jahn-Teller effect, resulting in improved Li transfer kinetics with a significantly reduced Li electroplating overpotential. Based on the mutually improved Li diffusion and adsorption kinetics, the Li adsorbent is used as a versatile host to enable dendrite-free and stable Li metal anodes in LMBs. Consequently, a modified Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) coin cell with a high NMC811 loading of 4.3 mAh cm-2 delivers a high Coulombic efficiency of 99.85% over 200 cycles and the modified Li||NMC811 pouch cell also achieves a remarkable improvement in electrochemical performance. This work demonstrates a novel approach for the preparation of highly efficient Li protection structures for safe LMBs with long lifespans

Fast Li⁺ Transfer Scaffold Enables Stable High-Rate All-Solid-State Li Metal Batteries

Sluggish transfer kinetics caused by solid–solid contact at the lithium (Li)/solid-state electrolyte (SE) interface is an inherent drawback of all-solid-state Li metal batteries (ASSLMBs) that not only limits the cell power density but also induces uneven Li deposition as well as high levels of interfacial stress that deteriorates the internal structure and cycling stability of ASSLMBs. Herein, a fast Li+ transfer scaffold is proposed to overcome the sluggish kinetics at the Li/SE interface in ASSLMBs using an α-MnO2-decorated carbon paper (CP) structure (α-MnO2@CP). At an atomic scale, the tunnel structure of α-MnO2 exhibits a great ability to facilitate Li+ adsorption and transportation across the inter-structure of α-MnO2@CP, leading to a high critical current density of 3.95 mA cm−2 at the Li/SE interface. Meanwhile, uniform Li deposition can be guided along the skeletons of α-MnO2@CP with minimized volume expansion, significantly improving the structural stability of the Li/SE interface. Based on these advantages, the ASSLMBs using α-MnO2@CP protected the Li anode and can stably cycle up to very high charge/discharge rates of 10C/10C, paving the way for developing high-power ASSLMBs

Synthesis and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 cathodes in lithium-ion and all-solid-state lithium batteries

LiNi1/3Co1/3Mn1/3O2 cathodes have been prepared by a solid-state reaction process. The effects of calcination and post-annealing temperature on electrochemical performances were systematically investigated for both of the lithium-ion batteries with liquid electrolytes and all-solid-state lithium batteries with sulfide solid electrolytes. The particle size of the LiNi1/3Co1/3Mn1/3O2 materials increases with calcination temperatures, whereas after calcination, the shape and size of LiNi1/3Co1/3Mn1/3O2 particles were independent of post-annealing temperatures. The LiNi1/3Co1/3Mn1/3O2 calcinated at 850 A degrees C and followed by post-annealing at 800 A degrees C maintains 97.6 % capacity retention after 30 cycles and has a capacity of 117 mAh g(-1) at a current of 5 C (current density of 24.1 mA/cm(2)) in a voltage range of 2.8 and 4.3 V in lithium-ion batteries. Moreover, the optimal sample has the first discharge capacity of about 115 mAh g(-1) at a current density of 0.11 mA cm(-2) in the all-solid-state lithium battery with Li10GeP2S12 as solid state electrolyte. Electrochemical impedance spectroscopy measurements show that the post-annealing process plays an important role in suppressing the increase of cell impedance during charging-discharging. The experimental results suggest that the post-annealed LiNi1/3Co1/3Mn1/3O2 material is very suitable as one of the leading cathode materials for lithium-ion and solid-state lithium batteries with long cycle life and high power density

Preparation and electrochemical performances of high voltage nanosized Al_2O_3 coating LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2

A layer of nano Al_2O_3 was coated on the surface of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 particles by sol-gel method, so the cycle performance and rate capability of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 at a high cut-off voltage are enhanced. The structure and morphology of the materials were characterized by XRD, SEM and TEM. The electrochemical performances of the high voltage cathodes were galvanostatically evaluated. The results show that the structure of the materials does not change after coating. The optimized coating content of Al_2O_3 is 2.0%, corresponding to the layer of 20-30 nm. The electrochemical performances of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 cathode materials are obviously improved by the Al_2O_3 layer. At the range of 2.8-4.5 V, the first discharge specific capacity of uncoated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 materials is 175 mAh/g at 0.2 C, and the capacity retention after 50 cycles is 91.8%. At the same charge-discharge conditions, the first specific discharge capacity of coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 materials increases to 181 mAh/g, and the capacity retention after 50 cycles still reaches 97.4%. Even at 5 C, the discharge specific capacity of coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 materials is 152 mAh/g. The coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 materials exhibit huge potential in the lithium ion batteries with high energy density and long cycle life

The Role of Gut Microbiota in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare, disabling inflammatory disease of the central nervous system (CNS). Aquaporin-4 (AQP4)-specific T cells play a key role in the pathogenesis of NMOSD. In addition to immune factors, T cells recognizing the AQP4 epitope showed cross-reactivity with homologous peptide sequences in C. perfringens proteins, suggesting that the gut microbiota plays an integral role in the pathogenicity of NMOSD. In this review, we summarize research on the involvement of the gut microbiota in the pathophysiology of NMOSD and its possible pathogenic mechanisms. Among them, Clostridium perfringens and Streptococcus have been confirmed to play a role by multiple studies. Based on this evidence, metabolites produced by gut microbes, such as short-chain fatty acids (SCFAs), tryptophan (Trp), and bile acid (BA) metabolites, have also been found to affect immune cell metabolism. Therefore, the role of the gut microbiota in the pathophysiology of NMOSD is very important. Alterations in the composition of the gut microbiota can lead to pathological changes and alter the formation of microbiota-derived components and metabolites. It can serve as a biomarker for disease onset and progression and as a potential disease-modifying therapy

Selenium-Infused Ordered Mesoporous Carbon for Room-Temperature All-Solid-State Lithium-Selenium Batteries with Ultrastable Cyclability

\Selenium with a similar reaction mechanism with sulfur and a much higher electronic conductivity is considered to be a promising cathode for all-solid-state rechargeable batteries. Herein, selenium-infused ordered mesoporous carbon composites (Se/CMK-3) are successfully prepared by a melt-diffusion method from a ball-milled mixture of Se and CMK-3 (Se-CMK-3). Furthermore, their electrochemical performances are evaluated in all-solid-state lithium-selenium batteries at room temperature. Typically, Li/75%Li2S-24%P2S5-1%P2O5/Li10GeP2S12/Se/CMK-3 all-solid-state lithium-selenium batteries exhibit high reversible capacity of 488.7 mAh g(-1) at 0.05 C after 100 cycles. Even being cycled at 0.5C, it still maintains a discharge capacity of 268.7 mAh g(-1) after 200 cycles. The excellent electrochemical performances could be attributed to the enhanced electronic/ionic conductivities and structural integrity with the addition of the CMK-3 matrix

Effective Strategy for Enhancing the Performance of Li4Ti5O12 Anodes in Lithium-Ion Batteries: Magnetron Sputtering Molybdenum Disulfide-Optimized Interface Architecture

Effective Strategy for Enhancing the Performance of Li4Ti5O12 Anodes in Lithium-Ion Batteries: Magnetron Sputtering Molybdenum Disulfide-Optimized Interface Architectur