Fluorine-Doped Li7La3Zr2O12 Fiber-Based Composite Electrolyte for Solid-State Lithium Batteries with Enhanced Electrochemical Performance.

Garnet-based electrolytes with high ionic conductivity and excellent stability against lithium metal anodes are promising for commercial applications in solid-state lithium batteries (SSLBs). However, the further development of SSLBs is inhibited by issues such as low ionic conductivity and uncontrolled lithium dendrite growth. Herein, we report the synthesis of fluorine-doped Li7La3Zr2O12 (LLZO-F0.2) fibers by electrospinning and the subsequent calcination at high temperatures. The solid composite electrolyte with LLZO-F0.2 exhibits an ionic conductivity of 5.37 × 10-4 S cm-1 and a high lithium-ion transference number of 0.61 at room temperature. Meanwhile, it exhibits lower resistance and more uniform lithium metal stripping and deposition in symmetric cells. The full cell with LiFePO4 cathode exhibits excellent rate capability and cycling stability for 800 cycles at 0.5 C with a discharge specific capacity retention of 97.7%. This fluorine-doped fibrous garnet-type electrolyte provides a viable option for preparing high-performance SSLBs.

Robust Solid-State Na-CO2 Battery with Na2.7Zr2Si2PO11.7F0.3-PVDF-HFP Composite Solid Electrolyte and Na15Sn4/Na Anode.

Solid-state Na-CO2 batteries are a kind of energy storage devices that can immobilize and convert CO2. They have the advantages of both solid-state batteries and metal-air batteries. High-performance solid electrolyte and electrode materials are important for improving the performance of solid-state Na-CO2 batteries. In this work, we investigate the influence of fluorine doping on the structure and ionic conductivity of Na3Zr2Si2PO12 (NZSP). An ionic conductive solid electrolyte membrane was prepared by compositing the inorganic solid electrolyte Na2.7Zr2Si2PO11.7F0.3 (NZSPF3) with poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP). It shows an ionic conductivity of up to 2.17 × 10-4 S cm-1 at room temperature, a high sodium ionic transfer number of ∼0.70, a broad electrochemical window of ∼5.18 V, and better mechanical strength. Furthermore, we studied the Na15Sn4/Na composite foil with the ability to inhibit dendrite as the anode for solid-state Na-CO2 batteries. Through density functional theory (DFT) calculations, the Na15Sn4 particle has been verified with a strong sodiophilic property, which reduces the nucleation barrier during the deposition process, leading to a lower overpotential. The symmetric cell assembled with the composite solid-state electrolyte NZSPF3-PVDF-HFP and Na15Sn4/Na composite anode can inhibit the growth of Na dendrites effectively and maintain the stability of the whole cell structure. Solid-state Na-CO2 batteries assembled with Ru-carbon nanotube (Ru-CNTs) as cathode catalysts exhibit a high discharge capacity of 6371.8 mAh g-1 at 200 mA g-1, excellent cycling stability for 1100 h, and good rate performance. This work provides a promising strategy for designing high-performance solid-state Na-CO2 batteries.

Dendrite-Free Lithium Metal Anodes Enabled by an Ordered Conductive Ni-Based Catecholate Interlayer for Solid-State Lithium Batteries.

The large-scale commercial application of Li metal batteries is hindered by uncontrolled Li dendrite growth. Most of the present interfacial engineering strategies in lithium metal batteries can only prolong the nucleation time of lithium dendrites but cannot prevent the growth of lithium dendrites in three-dimensional space. In this work, a nickel-based catecholate (Ni-CAT) conductive interlayer that can guide the orderly migration of lithium ions and inhibit the disordered deposition of lithium dendrites is successfully constructed between the solid electrolyte and lithium metal through a reasonable design. The experimental analysis proves that the Ni-CAT nanorod arrays with unique vertical structures are closely connected to the solid electrolyte, which can reduce the charge-transfer resistance at the interface and guide lithium ions to be preferentially deposited on the surface of the Ni-CAT intermediate layer through the conduction gradient. Hence, this structure effectively avoids the phenomenon of apical growth during lithium deposition. In addition, the rich pores and inherent nanochannels of Ni-CAT itself act as an "ion sieve", successfully inducing the uniform deposition of lithium metal, which greatly reduces the occurrence of dead lithium due to the loss of electrical contact of lithium during cycling. This strategy holds promise for solving the lithium dendrite problem.

Reducing graphene oxide carbon skeleton supported P-N heterostructure of bimetallic sulfide CoS-MoS2 nanorods for high-performance lithium storage.

Constructing bimetallic sulfide components are considered to be a promising and efficient lithium storage materials. Nonetheless, preparation routes of rational structures that have abundant hierarchical interfaces or phase boundaries bimetallic sulfide are still a problem to over come. In this work, a novel hierarchical nanostructure of bimetal sulfide CoS-MoS2 nanorods are synthesized successfully by in-situ self-growth means at the hydrothermal conditions. Subsequently, we loaded it to the carbon matrix (CoS-MoS2@rGO) forming a three-dimensional structures with the help of freeze drying technology. This well-designed hierarchical structure could created a stable heterogeneous contact surface, which guarantees rapid Li+ ions diffusion and facilitates charge transfer at the heterointerface. Which can maintain capacity of 776 mAh/g over 800 cycles at 1 A/g. On the other hand, it shows an excellent rate capability of 464 mAg h-1 at 5 A/g. From the perspective of electrochemical kinetics, we analyze and explore the reason about the improved lithium storage performance. Furthermore, to insight into the relationship between matter and phase conversion, the in-situ X-ray diffraction characterization is executed. The strategy of rationally designing hierarchical heterostructures will shed light on outstanding electrochemical performance in energy storage applications.