Transforming waste anthracite-to-energy, mesoporous anode for lithium dual-ion batteries based on the position control of SiC and SiO2

초록

Due to the global environmental issues, recycling must be considered in all industries. We recycle anthracite, which is becoming a waste resource as demand decreases, as an energy storage material. Porous artificial graphite (PAG) derived from anthracite is a major host material with ball milling and annealing methods, which are advantageous for scale-up. Ammonium bicarbonate (ABC) is used as a dynamic gas-templating agent to direct the in-situ formation and distribution of Si, SiC, and SiO2 within PAG's porous framework. The mesoporous SiC@Si@SiO2-C composite anode (21 wt% Si) finally formed possesses SiC and SiO2, and their unique positional arrangement leads to enhanced graphitization, defect engineering, and interfacial modulation. SiC layers passivate silicon surfaces, mitigating mechanical stress, while embedded SiO2 stabilizes the solid electrolyte interphase (SEI). Advanced electron microscopy confirms the local position of SiC and SiO2 in the low carbon density region. The resulting composite delivers high electronic conductivity, accommodates volume fluctuations, and accelerates lithium-ion kinetics. Electrochemical evaluation reveals a capacity retention of 88.7 % (563.1 mAh g-1) after 100 cycles and 71.3 % retention at 1 A g-1 over 300 cycles. In addition, the special arrangement effect of SiC and SiO2 is demonstrated by the phenomenon in which the slope becomes a plateau in the voltage profile. When paired with expanded graphite cathodes in dual-ion full cells, the anode achieves energy densities up to 501.6 Wh kg-1 (based on the active mass of the anode). This study demonstrates a scalable and sustainable route to multifunctional carbon-based anodes, leveraging coal-derived resources for next generation energy storage applications.

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