A facile procedure was provided to obtain amorphous Si 3 N 4 powder via a liquid-phase method, followed by a heat treatment process to realize tailorable shapes for α-Si 3 N 4 crystal, while Si 3 N 4 granules were synthesized and whiskers were inhibited. The influence of the temperature on the particle morphology and growth mechanisms were investigated. Characterizations indicated that the crystallization temperature played an important role in controlling the morphology of α-Si 3 N 4 powder, while the relatively lowly temperature (below 1519 °C) was beneficial to forming whiskers. The growth of Si 3 N 4 whiskers, derive from the reaction between SiO(g) and N 2 , follows the vapor–solid (VS) mechanism, which is inhibited by the increase in temperature. Instead, higher temperatures were conducive to forming granular structures. Highly crystalline α-Si 3 N 4 granules were prepared at 1550 °C due to Si*(g) and N*(g) recombining to Si 3 N 4 nuclei via the vapor–solid-solid (VSS) mechanism providing a theoretical basis for inhibiting the production of the whiskers.
Three-dimensional porous graphene (3DPG) has been widely used as electrode material for supercapacitors due to its high conductivity and high specific surface area. Herein, 3DPG with controllable three-dimensional (3D) morphologies was successfully synthesized via using sodium ascorbate (SA) and ethylenediamine (EDA) by a one-step low-temperature method. The porous structure and reductive degree of the 3DPG can be tuned by adjusting the addition amount of reducing agent and pH value of graphene oxide (GO) suspension, and the pore size and specific capacitance of the 3DPG gradually increased with the suitable increase of EDA and SA. Moreover, we found that the alkaline environment is more conducive to the synthesis of 3DPG than acid environment. It is worth mentioning that the specific capacitance of the as-prepared 3DPG reached a high value for 169 F g−1 when the suitable addition amount of reducing agent and pH value was given.
The all-solid-state lithium batteries (ASSLBs) stand as a promising candidate for the next generation of high-energy-density batteries with superior safety. Nevertheless, achieving high energy density in ASSLBs necessitates the simultaneous realization of high active material content and loading, posing a significant challenge in ensuring effective Li-ion conduction within the cathode. Notably, the inhomogeneous distribution of cathode particles causes high porosity and tortuosity within the composite cathodes, thereby adversely impacting the electrochemical performance of the battery. Herein, an in situ liquid-phase method for the fabrication of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) composite cathode is proposed. This strategy ensures the generation of uniformly distributed and densely packed composite cathode, establishing a well-networked conduction path that ensures exceptional electronic and ionic conductivity. ASSLBs utilizing LP-cathode exhibit outstanding electrochemical performance. It delivers a high capacity of 233.3 mAh g −1 at 0.05 C with superior rate capability and remarkable long-term cycling stability. Moreover, ASSLBs manifest exceptional electrochemical performance, even at a high cathode active material content of 80%. This underscores the efficacy of the liquid-phase method in constructing low-tortuosity electrodes and accelerating charge transport kinetics, thereby enhancing the overall performance of ASSLBs. This approach holds promise for addressing the challenges associated with achieving high energy density and facilitating the development of ASSLBs.
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