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Magnesium hydride (MgH2) has been recognized as a promising anode material of lithium‐ion batteries (LIBs) owing to its ultrahigh specific capacity. The low conductivity and the structural pulverization induced by large volume expansion, however, has long limited its practical lithium storage performance. Herein, a series of yolk‐shell‐like structures, composed of porous MgH2 nanoparticles (NPs) decorated with Mg‐based composites through in‐situ solid‐gas reaction using MgH2 as both the reactant and the structural template, have been fabricated and uniformly dispersed on electronically conductive graphene. It could not only physically accommodate the volume change of MgH2 owing to the physical protection of Mg‐based composites and the formation of void space inside MgH2 NPs, but also effectively facilitate the transportation of electrons throughout the whole electrode. Particularly, the uniform decoration of ultrathin Mg(BH4)2 as the shell with thermodynamically favorable intercalation of lithium ions and low kinetic barrier for the lithium‐ion diffusion promotes facile transportation of lithium ions into active MgH2, which, coupled with the porous structure constructed by flexible graphene, effectively improves the ion conductivity of the electrode. The synergistic improvement in electronic and ionic conductivity leads to a high reversible capacity of 1651 mAh g−1 at 200 mA g−1 after 380 cycles. [ABSTRACT FROM AUTHOR]

Aluminum–Sulfur (Al–S) batteries are regarded as promising energy storage devices due to their high energy‐to‐price ratios and safety. However, they suffer from clumsy S ↔ Al2S3 reactions and short lifespans that limit their practical application. By combining the merits of adsorptive Cu, catalytic Co, and conductive N‐doped carbon matrix, the bimetals decorated N‐doped carbon (Cu1Co1@NC) enables smooth adsorption and conversion of polysulfides. Consequently, the S@Cu1Co1@NC exhibits excellent electrochemical performance (delivering a high capacity of 317.5 mAh g−1 after 320 cycles at 1.5 A g−1). Moreover, the Cu‐endowed strong Al affinity and robust 3D scaffold with Co‐enhanced conductivity can regulate Al3+ depositing/stripping and successfully suppress Al dendrites. As a result, the Cu1Co1@NC displays negligible Al nucleation overpotential and provides ultra‐long lifespan (>10 000 h) and exceptional reversible (Coulombic efficiency = 99.8–99.9%) Al3+ plating/stripping. Integrating all these advantages, a full Al–S cell constructed with Cu1Co1@NC as two‐in‐one hosts demonstrates excellent capacity retention with enhanced reversibility. This work provides insights into the design of promising Al–S batteries based on bifunctional CuCo bimetal and favorable 3D framework. [ABSTRACT FROM AUTHOR]

Although MgH2 is widely regarded as one of the most promising solid-state hydrogen storage materials, the high operating temperature and sluggish kinetics of hydrogenation and dehydrogenation are major challenges for its practical application. Herein, V6O13 nanobelts with a thickness of 11 nm are fabricated to promote the reversible hydrogen storage performance of MgH2. The favorable interaction between V6O13 nanobelts and MgH2 leads to in situ homogeneous formation of metallic V during the initial dehydrogenation of MgH2. Induced by the catalysis of metallic V, which results in weaker structural stability and higher surface states of MgH2 attributed to the strong bonding interactions between V and H, the energy required for H2 desorption from MgH2 is decreased to 49.5 kJ mol−1, 10.9 kJ mol−1 lower than that of pristine MgH2. Moreover, during the reversible hydrogenation process, the catalysis of metallic V lowers the energy for H2 adsorption and dissociation on Mg down to −5.904 and 0.023 eV, respectively, while those values reach −0.086 and 1.103 eV for pristine Mg. As a result, with the introduction of V6O13 nanobelts with an ultralow content of 3 wt%, a systematic hydrogen storage capacity of 6.8 wt% could be retained at 250 °C after 10 cycles. [ABSTRACT FROM AUTHOR]

Owing to the low‐cost, safety, and three‐electron redox properties of aluminum, rechargeable aluminum‐ion batteries (AIBs) are emerging as a promising energy storage technology. However, exploring suitable cathode material with both elevated working voltage and high reversible capacity remains a daunting challenge. Herein, under the guidance of density functional theory calculations, V6O13 is proposed as a promising cathode candidate in AIBs for the first time. It is demonstrated that aluminum ions are reversibly stored in V6O13 by intercalation reactions, with a high discharge voltage plateau of ≈1.1 V. Of particular note a pre‐lithiation strategy is employed to further promote the redox kinetics, which endows the pre‐lithiated V6O13 nanobelt (Li–VONB) with improved capacity of 161.6 mAh g−1 and impressive energy density of 177.7 Wh kg−1 after 300 cycles, far higher than other reported oxide cathodes in AIBs. Moreover, the shielding effect of pre‐inserted Li and accelerated diffusion rate are uncovered at the atomic scale. This work develops a novel Li–VONB cathode for high‐energy AIBs, and shows the great potential of pre‐intercalation strategies in the application of AIBs. [ABSTRACT FROM AUTHOR]

Sodium borohydride (NaBH4) has been widely regarded as a potential hydrogen storage material due to its high gravimetric and volumetric capacity. Its practical application, however, is hindered by the high operating temperature of over 500 °C and extremely poor reversibility. Herein, thermodynamically favored reversible hydrogen storage performance of NaBH4 is developed inside of bimetallic (NiCo) nanoporous carbon nanosheets. Benefiting from the synergetic effect of nanoconfinement and the catalytic role of NiCo alloys, the apparent activation energy for H2 desorption from NaBH4@NiCo-NC is reduced to 36.8 kJ mol−1 with the complete H2 desorption at only 400 °C, resulting in the simultaneous formation of NiB and CoB as the dehydrogenation products. More interestingly, the reversible transformation between NiB/CoB and Ni2B/Co2B that are in situ formed during the subsequent re-/dehydrogenation process acts as a B reservoir, leading to a significant decrease of Gibbs free energy change for the reversibility of NaBH4 to 1.41 eV, 0.62 eV lower than that of pure NaBH4. As a result, coupled with the catalytic role of in situ formed Co2B/Ni2B in promoting the H2 desorption performance of NaBH4, a stable reversible capacity of 9.0 wt% is realized for NaBH4 at a temperature as low as 400 °C for 5 cycles. [ABSTRACT FROM AUTHOR]