Manganese sulfide (MnS) has triggered great interest as an anode material for rechargeable Li-ion/Na-ion batteries (LIBs/SIBs) because of its low cost, high electrochemical activity, and theoretical capacity. Nevertheless, the practical application is greatly hindered by its rapid capacity decay lead by inevitable active dissolutions and volume expansions in charge/discharge cycles. To resolve the above issues in LIBs/SIBs, we herein put forward the smart construction of MnS nanowires embedded in carbon nanoreactors (MnS@C NWs) via a facile solution method followed by a scalable in situ sulfuration treatment. This engineering protocol toward electrode architectures/configurations endows integrated MnS@C NWs anodes with large specific capacity (with a maximum value of 847 mA h g–1 in LIBs and 720 mA h g–1 in SIBs), good operation stability, excellent rate capabilities, and prolonged cyclic life span. To prove their potential real applications, we have established the full cells (for LIBs, MnS@C//LiFePO4; for SIBs, MnS@C//Na3V2(PO4)3), both of which are capable of showing remarkable specific capacities, outstanding rate performance, and superb cyclic endurance. This work offers a scalable, simple, and efficient evolution method to produce the integrated hybrid of MnS@C NWs, providing useful inspiration/guidelines for anodic applications of metal sulfides in next-generation power sources.

Metallic Fe nanoparticles trapped in thick carbon nanoreactors are realized in situ via conventional gas-phase reactions. These derived nanohybrids exhibit unique self-adapting properties, with prominent anodic performance in terms of both stored capacity and cyclic durability when serving as anodes for Ni-Fe batteries.

The large amount of iron rust yielded in steel industries is undoubtedly a useless and undesired product since its substantial formation and recycle/smelting would give rise to enormous financial costs and environmental pollution issues. To best reuse such rusty wastes, we herein propose a smart and applicable method to convert them into uniform α-Fe 2 O 3 nanospheres. Only after a simple and conventional hydrothermal treatment in HNO 3 solution, nearly all of the iron rust can evolve into sphere-like α-Fe 2 O 3 products with a typical size of ∼30 nm. When serving as actives for electrochemical energy storage, the in situ generated α-Fe 2 O 3 nanospheres exhibit prominent anodic performance, with a maximum specific capacity of ∼269 mAh/g at ∼0.3 A/g, good rate capabilities (∼67.3 mAh/g still retains even at a high rate up to 12.3 A/g), and negligible capacity degradation among 500 cycles. Furthermore, by paring with activated carbons/Ni cathodes, a unique full hybrid Ni−Fe cell is constructed. The assembled full devices can be operated reversibly at a voltage as high as ∼1.8 V in aqueous electrolytes, capable of delivering both high specific energy and power densities with maximum values of ∼131.25 Wh/kg and ∼14 kW/kg, respectively. Our study offers a scalable and effective route to transform rusty wastes into useful α-Fe 2 O 3 nanospheres, providing an economic way to make sustainable anodes for energy-storage applications and also a platform to develop advanced Fe-based nanomaterials for other wide potential applications.

Ferruginous materials have long attracted great interest in aqueous batteries since Fe is an earth-abundant and low toxic element. However, their practical application is severely hindered by their poor structural stability during deep cycling. To maximize their cyclability, we herein propose a simple and effective method, by in situ packaging Fe-based materials into carbon nanosacks via a facile CVD approach. To verify our strategy, we purposely choose water-soluble Fe2F5 as a study paradigm. The in situ formed Fe2F5@C nanosacks product exhibits prominent anodic performance with high electrochemical activity and capacity, obviously prolonged cyclic lifetime, and outstanding rate capabilities. Besides, by pairing with the cathode of α-Co(OH)2 nanowire arrays@carbon cloth, a full device of rechargeable aqueous batteries has been developed, capable to deliver both high specific energy and power densities (Max. values reaching up to ∼163 Wh kg(-1) and ∼14.2 kW kg(-1)), which shows great potential in practical usage. Our present work may not only demonstrate the feasibility of using soluble fluorides as anodes for aqueous batteries but also provide a smart way to upgrade cyclic behaviors of Fe-based anodes.

Iron fluorides (FeF x ) for Li-ion battery cathodes are still in the stage of intensive research due to their low delivery capacity and limited lifetime. One critical reason for cathode degradation is the severe aggregation of FeF x nanocrystals upon long-term cycling. To maximize the capacity and cyclability of these cathodes, we propose herein a novel and applicable method using a thin-layered nickel ammine nitrate (NAN) matrix as a feasible encapsulation material to disperse the FeF 3 nanoparticles. Such core−shell hybrids with smart configurations are constructed via a green, scalable, in situ encapsulation approach. The outer thin-film NAN matrix with prominent electrochemical stability can keep the FeF 3 nanoactives encapsulated throughout the cyclic testing, protecting them from adverse aggregation into bulk crystals and thus leading to drastic improvements of electrode behaviors (e.g., high electrode capacity up to ∼423 mA h g −1 , greatly prolonged cyclic period, and promoted rate capabilities). This present work may set up a new and general platform to develop intriguing core−shell hybrid cathodes for Li-ion batteries, not only for FeF x but also for a wide spectrum of other cathode materials.