Collision Energy Analysis within the Vertical Shaft Impact Crusher Based on the Computational Fluid Dynamics-Discrete Element Method.

Particles in the vertical shaft impact crusher absorb and dissipate collision energy in the impact breakage. The distribution of the collision energy determines the breakage rate of materials and breakage energy consumption of the entire system. In this paper, the gas-solid coupling method is used to explore the regional distribution of collision energy, collision frequency, and collision energy spectrum of the material particle groups. Hence, a theoretical basis is provided for the efficient and energy-saving design of the crusher. First, a coupling mathematical model of the computational fluid dynamics and discrete element method is established to describe the interaction between material and fluid in the crushing chamber. Moreover, the experiment is carried out using a PL8500 VSI crusher and compared with the simulation results to verify the model's reliability. Finally, the effects of different working conditions on the energy dissipation distribution and energy spectrum are explored. The results show that the collision energy within the crushing chamber can be accurately predicted by using the fluid-solid coupling model. Moreover, increasing the rotational speed can effectively transform low-energy collision events into high-energy collisions and increase the collision frequency with energy dissipation above the threshold energy. Thus, the probability of material breakage is increased. Last, increasing the feed rate minorly affects the material breakage rate, while the specific energy of the entire system is reduced.

Interconnected Three-Dimensional Porous Alginate-Based Gel Electrolytes for Lithium Metal Batteries.

Lithium batteries have been widely used in our daily lives for their high energy density and long-term stability. However, their safety problems are of paramount concern for consumers, which restricts their scale applications. Gel polymer electrolytes (GPEs) compensate for the defects of liquid leakage and lower ionic conductivity of solid electrolytes, which have attracted a lot of attention. Herein, a 3D interconnected highly porous structural gel electrolyte was prepared with alginate dressing as a host material, poly(ethylene oxide) (PEO), and a commercial liquid electrolyte. With rich polar functional groups and (CH2-CH2-O) segments on the polymer matrix, the transportation of Li+ is faster and uniform; thus, the formations of lithium dendrite were significantly inhibited. The cycle stability of symmetrical Li||Li batteries with modified composite electrolytes (SAA) is greatly improved, and the overpotential remains stable after more than 1000 h. Meanwhile, under the same conditions, the cycle performance of batteries with unmodified electrolytes is inferior and overpotentials are nearly 1 V after 100 h. Additionally, the capacity retention of Li||LiFePO4 with SAA is more than 95% after 200 cycles, while those of the others declined sharply. The alginate dressing-based GPEs can greatly enhance the mechanical and thermal stability of PEO-based GPEs, which provides an environmentally friendly avenue for gel electrolytes' applications in lithium batteries.