Stannic oxide (SnO 2 )-based lithium-ion batteries (LIBs) have garnered tremendous attention due to their high theoretical capacity and suitable lithium ion insertion potential. However, their widespread applications have been hindered by severe electrode degradation caused by substantial volume expansion of SnO 2 . In this study, we embedded amorphous carbon encapsulated ultrafine SnO 2 nanoparticles on hollow macroporous carbon (AC@SnO 2 /HMC) as a superior anode material for LIBs. The unique Sn–C interface and dual carbon protection layers effectively mitigated SnO 2 nanoparticle agglomeration and volume expansion, reinforcing the cycling stability. Additionally, the capacitive contribution from amorphous carbon significantly improved the reversible capacity and rate capability. As such, the resulting AC@SnO 2 /HMC electrode exhibited high capacity (1828 mAh g −1 after 200 cycles at 0.1 A g −1 ), excellent rate capability (1017.6 mAh g −1 at 1 A g −1 ), and outstanding cycling performance (792.1 mAh g −1 after 880 cycles at 2 A g −1 ), surpassing previously reported SnO 2 -based anodes. Furthermore, the AC@SnO 2 /HMC-based Li-ion full cell demonstrated a remarkable capacity of 566.3 mAh g −1 at 0.2 A g −1 after 200 cycles. This study offers valuable insights into the development of advanced SnO 2 -based anodes for LIBs and beyond, highlighting their potential for future advancements in battery technology.
Menghan Yu,Yicheng Hua,Muhammad Tariq Sarwar,Huaming Yang
The concentrations of terrestrially sourced dissolved organic matter (DOM) have expanded throughout aquatic ecosystems in recent decades. Although sorption to minerals in soils is one major pathway to sequestrate soil organic matter, the mechanisms of organic matter–mineral interactions are not thoroughly understood. Here, we investigated the effect of calcium phosphate mineralization on humic acid (HA) fixation in simulated soil solutions, either with or without clay mineral montmorillonite (Mt). We found that Mt in solution promoted nucleation and crystallization of calcium phosphate (CaP) due to amorphous calcium phosphate clustering and coalescence on Mt surface, which contributed to the long-term persistence and accumulation of HA. Organic ligands with specific chemical groups on HA have higher binding energies to CaP–Mt than to CaP/Mt, according to dynamic force spectroscopy observations. Moreover, CaP–Mt formed in solution showed a great capacity for HA adsorption with a maximum adsorption quantity of 156.89 mg/g. Our findings directly support that Mt is crucial for DOM sequestration by facilitating CaP precipitation/transformation. This has an impact on how effectively we understand the long-term turnover of DOM and highlights knowledge gaps that might assist in resolving essential soil C sequestration issues.
Manganese-based cathode materials are promising candidates for aqueous zinc ion batteries (AZIBs) by reason of their low cost and high energy density. However, their practical applicability is hampered by the intrinsic defects of poor electrical conductivity, sluggish reaction kinetics, and severe structural deterioration. Herein, we constructed a hierarchically porous structure composed of carbon-encapsulated MnO nanoparticles (MOC) and three-dimensional (3D) nitrogen-doped graphene aerogel (NGA) (denoted as MOC@NGA). The hybrid was synthesized by a facile in-situ coprecipitation and annealing of manganese-based metal-organic framework (Mn-MOF74) and NGA composite (Mn-MOF74@NGA). Specifically, the carbon shells inherited from organic ligand of Mn-MOF74 could restrain the volume changes of MnO, and the porous NGA prevented the agglomeration of MOC nanoparticles and enriched the types of interfacial chemical bonds. Profiting from the synergistic effect of rich interface chemical bonds and dual-carbon protection, the MOC@NGA hybrids exhibit fast interfacial electron/charge transfer and transport, and outstanding structural stability. Therefore, MOC@NGA cathode delivers an excellent rate performance (270 and 99.8 mAh g −1 at 0.1 and 2.0 A g −1 ) and maintains an excellent specific capacity of 151.6 mAh g −1 after 2,000 cycles at 1.0 A g −1 . Moreover, the fabricated MOC@NGA-based quasi-solid-state battery not only achieves outstanding flexibility but also displays impressive cycling stability, demonstrating a promising potential for portable and flexible equipment. This work provides a feasible strategy for the fabrication of the bridging structure of manganese-based oxides and porous carbon matrix for high-specific capacity and durable AZIBs cathodes.
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