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Nonmetals reclaimed from waste phenolic cellulose paper printed circuit boards (PCBs) are used to replace wood flour in the production of phenolic molding compound (PMC). The results indicate that filling of nonmetals in PMC improves the charpy notched impact strength and heat deflection temperature (HDT) and reduces flexural strength and rasching fluidity. Rasching fluidity decreases dramatically with the increase of the content of nonmetals. To ensure sufficient properties of PMC, the optimal added content of nonmetals is 20 wt %, which results in a flexural strength of 70 MPa, a charpy notched impact strength of 2.4 KJ/m2, a HDT of 168 degrees C, a dielectric strength of 3.9 MV/m, and a rasching fluidity of 103 mm, all of which meet the national standard data. When the added content of nonmetals is 20%, the charpy notched impact strength, HDT, and rasching fluidity of PMC decrease, and the flexural and dielectric strengths decrease at first and then increase with decreasing particle sizes. All the results indicate that making PMC with nonmetals of waste PCBs can resolve environmental pollution, reuse nonmetals in different fields, and provide a new method for resource utilization of nonmetals from waste PCBs.

Single-crystal lithium-nickel-manganese-cobalt-oxide (SC-NMC) has recently emerged as a promising battery cathode material due to its outstanding cycle performance and mechanical stability over the tradional polycrystalline NMC. It is favorable to further increase the grain size of SC-NMC particles to achieve a higher volumetric energy density and minimize surface-related degradations. However, the preparation of large-size yet high performance SC-NMC particles faces a challenge in choosing a suitable temperature for sintering. High temperature promotes grain growth but induces cation mixing that negatively impacts the electrochemical performance. Here we report a temperature-swing sintering (TSS) strategy with two isothermal stages that fulfils the needs for grain growth and structural ordering sequentially. A high-temperature sintering is first used for a short period of time to increase grain size and then the reaction temperature is lowered and kept constant for a longer period of time to improve structural ordering and complete the lithiation process. SC-LiNi0.6Mn0.2Co0.2O2 materials prepared via TSS exhibit large grain size (∼4 μm), a low degree of cation mixing (∼0.9%), and outperform the control samples prepared by the conventional sintering method. This work highlights the importance of understanding the process-structure-property relationships and may guide the synthesis of other SC Ni-rich cathode materials.

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