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.

Modulating the electronic structure of Mo2C/MoP heterostructure to boost hydrogen evolution reaction in a wide pH range.

Interface engineering is an effective strategy for the design of electrochemical catalysts with attractive performance for hydrogen evolution reaction. Herein, the Molybdenum carbide/molybdenum phosphide (Mo2C/MoP) heterostructure deposited on nitrogen (N), phosphorous (P) co-doped carbon substrate (Mo2C/MoP-NPC) is fabricated by one-step carbonization. The electronic structure of Mo2C/MoP-NPC is changed by optimizing the ratio of phytic acid and aniline. The calculation and experimental results also show that there is an electron interaction on the Mo2C/MoP interface, which optimizes the adsorption free energy of hydrogen (H) and improves the performance of hydrogen evolution reaction. Mo2C/MoP-NPC exhibits significant low overpotentials at 10 mA·cm-2 current density, 90 mV in 1 M KOH and 110 mV in 0.5 M H2SO4, respectively. In addition, it shows superior stability over a broad pH range. This research provides an effective method for the construction of novel heterogeneous electrocatalysts and is conducive to the development of green energy.