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Rechargeable aqueous Zn-metal batteries have attracted widespread attention owing to their safety and low cost beyond Li-metal batteries. However, due to the lack of the solid electrolyte interphase, problems such as dendrites, side reactions and hydrogen generation severely restrict their commercial applications. Herein, a quasi-liquid interphase (QLI) with a "solid–liquid" property is constructed to stabilize the Zn-metal anode. The synergistic effect of solid and liquid behavior ensures the stable existence of QLI and simultaneously enables the interphase dynamic and self-adaptive to the anode evolution. Electrolyte erosion, Zn2+ diffusion and side reactions are inhibited during long-term cycling after introducing QLI, significantly improving the cycling stability and capacity retention of the symmetric and full cells modified with QLI (Zn@QLI), respectively. Constructing an interphase with a quasi-liquid state represents a promising strategy to stabilize the metal anodes in aqueous electrolytes and even extend to organic electrolytes. [ABSTRACT FROM AUTHOR]

Increasing the energy density of lithium-ion batteries (LIBs) can broaden their applications in energy storage but remains a formidable challenge. Herein, with polyacrylic acid (PAA) as phase separation agent, macroporous Co2SnO4 with hollow skeletons was prepared by sol-gel method combined with phase separation. As the anode of LIBs, the macroporous Co2SnO4 demonstrates high capacity retention (115.5% at 200 mA·g−1 after 300 cycles), affording an ultrahigh specific capacity (921.8 mA h·g−1 at 1 A·g−1). The present contribution provides insight into engineering porous tin-based materials for energy storage. [ABSTRACT FROM AUTHOR]

Tin-based materials are promising anode candidates profiting from their high theoretical capacities compared with that of commercial graphite to enhance energy efficiency and power capabilities for secondary batteries. Herein, Dictyophora-shaped hierarchically porous Mn2SnO4/C composite materials were facilely prepared by a sol–gel process accompanied by phase separation, followed by a controllable two-step heat treatment. The heat treatment temperature and atmosphere have an important effect on the phase composition, pore structure and electrochemical performances of tin-based materials. The crystalline Mn2SnO4/C composite can be obtained via a two-step heat-treatment (first in air and then in argon), whereas a mixture of Mn3O4 and SnO2 will be achieved through a one-step heat-treatment in air. The synthesized hierarchically porous Mn2SnO4/C composite has 3D bicontinuous skeletons and a hierarchical micro–meso–macropore structure with wide pore size distribution, and has high reversible capacity (939.9 mA h g−1 at 200 mA g−1), and great rate retention (36.5% capacity retention from 0.1 to 10 A g−1), as well as good cycle stability, delivering a high specific capacity of 784.1 mA h g−1 at 1 A g−1 after 500 cycles. The enhanced performances can be attributed to the hierarchical pore structure, which not only assists electron and Li-ion transportation but also creates more active sites. The hierarchically porous electrode design strategy has potential in high-capacity and fast-rate energy storage devices. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) Nitrogen-doped carbon coated hierarchically porous silicon (hp-Si@NC) composite with cocontinuous skeletons and abundant interconnected macropores was prepared by a sol-gel route, followed by a magnesiothermic reduction and a polydopamine pyrolyzation. The BET specific surface area and pore volume of the obtained hp-Si@NC composite are calculated to be around 220.4 m2·g─1 and 0.247 cm3·g─1, respectively. Both hierarchically porous Si monolith and hp-Si@NC composite possess great electrochemical performances. The hierarchically porous Si monolith exhibits an initial discharge and charge capacity of about 1943 and 1621 mAh·g─1, and maintains a reversible capacity of about 125 mAh·g─1 in the 100th cycle. The hp-Si@NC composite reveals a discharge capacity of about 1077 mAh·g─1 and a charge capacity of 723 mAh·g─1 in the first cycle, and a reversible capacity of around 700 mAh·g─1 remains after 100 cycles. The coulombic efficiency increases from 67.1% in the first cycle to 97% in the second cycle and to 99% in the 100th cycle, with a great rate performance. All these favorable electrochemical characterizations benefit from unique pore structure and N-doped carbon layer. The hp-Si@NC composite obtained by integrating with sol-gel process, magnesiothermic reduction and polydopamine pyrolyzation can be promisingly applied as an anode in Li-ion batteries with a bright prospect. • Three-dimensional hierarchical porous Si monolith is prepared by a magnesiothermic reduction. • The hp-Si@NC composite possesses interconnected macropores and co-continuous skeletons. • The hierarchically porous hp-Si@NC shows excellent cycling stability and rate capability. [ABSTRACT FROM AUTHOR]