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The practical application of sodium (Na) metal anode has been seriously hindered by the uncontrolled Na dendrite growth and severe volume expansion inducing short battery lifespan and safety concerns. Here, highly sodiophilic and ultrafine ZnS‐modified carbon fibers have been rationally constructed as a scaffold to obviate these drawbacks. The in situ generated Na2S‐reinforced fast ion transport interphase and the effective space confinement synergistically facilitate the fast sodium ion interfacial transfer and the homogeneous and dendrite‐free Na deposition, thus enabling high‐rate and dendrite‐free Na metal anode. The modified Na metal demonstrates ultrahigh rate capability (15 mA cm−2) and ultralong cycling life (5300 cycles). Moreover, the Na|Na3V2(PO4)3 (NVP) cell delivers ultrahigh rate capability (80 C) and extraordinarily ultralong lifespan cycling durability (2980 cycles). The Na|NVP pouch cell also exhibits an extraordinarily ultralong‐term cycle life of over 1070 cycles with an extremely low capacity decay rate of 0.0088% per cycle at 10 C. This work provides a facile and efficient strategy to propel the Na metal anode towards practicability. [ABSTRACT FROM AUTHOR]

The practical utilization of Li metal anodes has been significantly plagued by the challenges of uncontrollable dendritic Li growth and poor interphase instability. Here, the study reports a novel strategy to strengthen interphase and give highly efficient active seeds concurrently to stabilize Li metal via a highly lithiophilic In2O3 decorated porous scaffold. In situ configurated fast‐ion‐transport Li2O‐strengthened interphase layer cooperatively with highly efficient Li13In3 nucleation induction can endow the uniform Li nucleation/growth and high Li utilization efficiency. As a result, the achieved modified Li metal manifests high Coulombic efficiency, ultrahigh rate performance (5 mA cm−2), and ultra‐long lifespan cycling durability (7975 cycles). Importantly, the established Li|LiFePO4 cells exhibit long‐term cycling durability over 600 cycles at 1 C with an ultralow decay rate of ca. 0.017% per cycle. Moreover, the Li|LiCoO2 pouch cells with ultrahigh areal capacity of ca. 3.89 mAh cm−2 also exhibit extraordinarily prolonged cycling performance with excellent capacity retention despite extremely harsh cycling conditions of low negative‐to‐positive‐capacity (N/P) ratio of ca. 1.7 and lean electrolyte of ca. 4.9 g Ah−1. This work enlightens a facile and effective avenue toward highly stable Li metal anode toward reliable practicability. [ABSTRACT FROM AUTHOR]

Searching for novel solid electrolytes is of great importance and challenge for all‐solid‐state Mg batteries. In this work, we develop an amorphous Mg borohydride ammoniate, Mg(BH4)2·2NH3, as a solid Mg electrolyte that prepared by a NH3 redistribution between 3D framework‐γ‐Mg(BH4)2 and Mg(BH4)2·6NH3. Amorphous Mg(BH4)2·2NH3 exhibits a high Mg‐ion conductivity of 5 × 10−4 S cm−1 at 75 °C, which is attributed to the fast migration of abundant Mg vacancies according to the theoretical calculations. Moreover, amorphous Mg(BH4)2·2NH3 shows an apparent electrochemical stability window of 0–1.4 V with the help of in‐situ formed interphases, which can prevent further side reactions without hindering the Mg‐ion transfer. Based on the above superiorities, amorphous Mg(BH4)2·2NH3 enables the stable cycling of all‐solid‐state Mg cells, as the critical current density reaches 3.2 mA cm−2 for Mg symmetrical cells and the reversible specific capacity reaches 141 mAh g−1 with a coulombic efficiency of 91.7% (first cycle) for Mg||TiS2 cells. [ABSTRACT FROM AUTHOR]

Boosting the ultralow temperature (below −30 °C) performance of Na‐ion hybrid capacitors (SIHCs), which integrate the high energy density of batteries with the high output power and long life of supercapacitors, is critical for the application of advanced electronics in extreme environments. However, their low‐temperature performance, especially fast charging capability, is hindered by difficult desolvation and slow pass solid electrolyte interphase (SEI) together with sluggish diffusion within the electrode. Herein, a "single‐solute–single‐solvent" electrolyte is developed and a through‐hole hollow carbon sphere (TH‐HCS) is constructed, and it is demonstrated through theoretical calculations and experimental investigations that the weakly solvated structure and high ionic conductivity facilitate the Na+ transportation at low temperatures, the highly fluorinated SEI facilitates the Na+ migration, and the through‐hole hollow structure alleviates the volume expansion during sodiation, thus ensuring fast kinetics and structural stability. As expected, TH‐HCS using this electrolyte exhibits a high specific capacity of 87.5 mAh g−1 after 11 000 cycles at 1.0 A g−1 and −40 °C. Coupled with activated carbon, the assembled SIHC displays an energy density of 106.1 and 52.0 Wh kg−1 at 25 and −40 °C, respectively, far exceeding the performance of commercial energy storage systems at low temperature. [ABSTRACT FROM AUTHOR]

A new Fe-substituted TiFeNb10O29−δ (TFNO) anode is proposed. TFNO possesses a defective and polycrystalline ReO3 Roth–Wadsley shear structure with a slightly larger lattice volume. Electrochemical behavior results and density functional theory (DFT) calculations show that TFNO can facilitate the kinetics of electron/Li+ transportation and demonstrates pseudocapacitive behavior. Consequently, TFNO exhibits superior high rate capacity and cycling stability compared to pristine TNO, offering 100 mA h g−1 at an ultrahigh rate of 50C and a high capacity retention of 86.7% over 1000 cycles at 10C. This work reveals that TFNO could be a promising anode material for fast-charging, stable, and safe LIBs. [ABSTRACT FROM AUTHOR]

As one of the most promising cathodes for sodium-ion batteries (SIBs), the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis. However, their applications are still hindered by the problems of poor moisture stability and sluggish Na+ diffusion caused by intrinsic structural Jahn—Teller distortion. Herein, we demonstrate a new approach to settle the above issues through introducing K+ into the structures of Ni/Mn-based materials. The physicochemical characterizations reveal that K+ induces atomic surface reorganization to form the birnessite-type K2Mn4O8. Combining with the phosphate, the mixed coating layer protects the cathodes from moisture and hinders metal dissolution into the electrolyte effectively. Simultaneously, K+ substitution at Na site in the bulk structure can not only widen the lattice-spacing for favoring Na+ diffusion, but also work as the rivet to restrain the grain crack upon cycling. The as achieved K+-decorated P2-Na0.67Mn0.75Ni0.25O2 (NKMNO@KM/KP) cathodes are tested in both coin cell and pouch cell configurations using Na metal or hard carbon (HC) as anodes. Impressively, the NKMNO@KM/KP||Na half-cell demonstrates a high rate performance of 50 C and outstanding cycling performance of 90.1% capacity retention after 100 cycles at 5 C. Furthermore, the NKMNO@KM/KP||HC full-cell performed a promising energy density of 213.9 Whkg−1. This performance significantly outperforms most reported state-of-the-art values. Additionally, by adopting this strategy on O3-NaMn0.5Ni0.5O2, we further proved the universality of this method on layered cathodes for SIBs. [ABSTRACT FROM AUTHOR]