An innovative approach for efficient synthesis of petal-like molybdenum disulfide nanosheets inside hollow mesoporous carbon spheres (HMCSs), the yolk-shell structured MoS@C, has been developed. HMCSs effectively control and confine in situ growth of MoS nanosheets and significantly improve the conductivity and structural stability of the hybrid material. The yolk-shell structured MoS@C is proven to achieve high reversible capacity (993 mA h g at 1 A g after 200 cycles), superior rate capability (595 mA h g at a current density of 10 A g), and excellent cycle performance (962 mA h g at 1 A g after 1000 cycles and 624 mA h g at 5 A g after 400 cycles) when evaluated as an anode material for lithium-ion batteries. This superior performance is attributed to the yolk-shell structure with conductive mesoporous carbon as the shell and the stack of two-dimensional MoS nanosheets as the yolk.

First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (η) significantly above thermodynamic requirements. Here, we report an iron/ nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm −2 in 1.0 KOH, with a small Tafel slope and excellent stability. The pHindependent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate.

Sulfur (S) is an attractive cathode material with advantages including high theoretical capacity and low cost. However, issues such as the lithium polysulfide shuttle effect and its insulating properties greatly limit the future applications of lithium‐sulfur (Li‐S) batteries. Here, a viscous aqueous ink with nanoscale S uniformly decorated on the polar, metallically conductive titanium carbide MXene nanosheets (S@Ti3C2Tx) is reported to address these issues. Importantly, it is observed that the conductive Ti3C2Tx mediator efficiently chemisorbs the soluble polysulfides and converts them into thiosulfate/sulfate. The in situ formed sulfate complex layer acts as a thick protective barrier, which significantly retards the shuttling of polysulfides upon cycling and improves the sulfur utilization. Consequently, the binder‐free, robust, highly electrically conductive composite film exhibits outstanding electrochemical performance, including high capacities (1244–1350 mAh g‐1), excellent rate handling, and impressive cycling stability (0.035–0.048% capacity loss per cycle), surpassing the best MXene‐S batteries known. The fabrication of a pouch cell based on the freestanding S@Ti3C2Tx film is also reported. The prototype device showcases high capacities and excellent mechanical flexibility. Considering the broad family of MXenes and their unique roles in immobilizing the polysulfides, various S@MXene composites can be similarly fabricated with promising Li+ storage capability and long lifetime performance.

The state-of-the-art development of fabrication strategies of multi-dimensional titanate and titania nanostructures is reviewed first. This is followed by an overview of their potential applications in environmental, energy, and biomedical sectors.

application. [ 1,2 ] However, bulk or microsize red P materials suffer from dramatic capacity reduction and poor cyclability with continued usage [ 1h ] due to their electronic insulation (≈10 −14 S cm −1 ) [ 1f ] and irreversible reaction related to the pulverization of particles, [ 1c , 3 ] which is caused by drastic volume change (>300%) [ 1h ] during cycling process. In light of this, black P is an alternative electrode material for high-performance LIB application due to its high electrical conductivity (≈10 2 S cm −1 ) [ 1h , 4 ] and fast kinetics during the Li + intercalating process. [ 4a,c ] Nevertheless, the traditional high-pressure method (>1 GPa, Scheme 1 a) through a pressure-induced structure-change mechanism is extremely diffi cult as it relies on specifi cally designed apparatus under controlled temperature (≥200 °C). [ 4c , 5 ] Recently, a facile mineralizer-assisted gas-phase transformation method was developed to produce large-size bulk black P. [ 6 ] However, the resultant particles by the above approaches are more than tens of micrometers in size, [ 5a , 6 ] which renders them unsuitable for high-rate LIB application. Therefore, material nanostructuring and engineering of the red/black P toward the improvement of electrical/ionic conductivity and the alleviation of volume expansion is desired for high-rate LIBs. [ 7 ] To this end, conductive confi gurations of nanostructured phosphorus materials (amorphous or red P, P-C composites, and metal phosphide, Scheme 1 a) [ 1d,e , 2e , 8 ] with buffering of volume change are widely explored through mechanical approaches (e.g., hand-grinding, mechanical milling, etc., as shown in Table S1, Supporting Information). [ 1f , 2a , 3,9 ] Furthermore, an emerging high energy mechanical milling by generating the suffi cient pressure (≈6 GPa) and temperature, [ 1c ] (Scheme 1 a), could even produce the most thermodynamically stable black P or composites with the particles size down to subhundred nanometer, which showed improved LIB performance. [ 1c,h ] Impressively, these nanostructured phosphorus or its composites [ 1d,e , 8 ] could realize high capacity (>1000 mAh g −1 ) as well as long-cycling life (>100 cycles) for LIBs. However, these top-down mechanical approaches remain diffi cult with respect to obtaining largescale uniform distribution of phosphorus nanostructures, as Phosphorus-based materials are promising for high-performance lithium-ion battery (LIB) applications due to their high theoretical specifi c capacity. Currently, the existing physical methods render great diffi culty toward rational engineering on the nanostructural phosphorus or its composites, thus limiting its high-rate LIB applications. For the fi rst time, a sublimation-induced synthesis of phosphorus-based composite nanosheets by a chemistry-based solvothermal reaction is reported. Its formation mechanism involves solidvapor-solid transformation driven by continuous vaporization-condensation process, as well as subsequent bottom-up assembly growth. The proof-o...