Sodium (Na) metal is a promising alternative to lithium metal as an anode material for the next-generation energy storage systems due to its high theoretical capacity, low cost, and natural abundance. However, dendritic/mossy Na growth caused by uncontrollable plating/stripping results in serious safe concerns and rapid electrode degradation. This study presents Sn 2+ pillared Ti 3 C 2 MXene serving as a stable matrix for high-performance dendrite-free Na metal anode. The intercalated Sn 2+ between Ti 3 C 2 layers not only induces Na to nucleate and grow within Ti 3 C 2 interlayers, but also endows the Ti 3 C 2 with larger interlayer space to accommodate the deposited Na by taking advantage of the "pillar effect," contributing to uniform Na deposition. As a result, the pillar-structured MXene-based Na metal electrode could enable high current density (up to 10 mA cm −2 ) along with high areal capacity (up to 5 mAh cm −2 ) over long-term cycling (up to 500 cycles). The full cell using MXene-based Na metal anode exhibits superior electrochemical performance than that using host-less commercial Na. It is believed that the well-controlled MXene-based Na anode not only extends the application scope of MXene, but also provides guidance in designing high-performance Na metal batteries.

A simple and template‐free method for preparing three‐dimensional (3D) porous γ‐Fe2O3@C nanocomposite is reported using an aerosol spray pyrolysis technology. The nanocomposite contains inner‐connected nanochannels and γ‐Fe2O3 nanoparticles (5 nm) uniformly embedded in a porous carbon matrix. The size of γ‐Fe2O3 nanograins and carbon content can be controlled by the concentration of the precursor solution. The unique structure of the 3D porous γ‐Fe2O3@C nanocomposite offers a synergistic effect to alleviate stress, accommodate large volume change, prevent nanoparticles aggregation, and facilitate the transfer of electrons and electrolyte during prolonged cycling. Consequently, the nanocomposite shows high‐rate capability and long‐term cyclability when applied as an anode material for Na‐ion batteries (SIBs). Due to the simple one‐pot synthesis technique and high electrochemical performance, 3D porous γ‐Fe2O3@C nanocomposites have a great potential as anode materials for rechargeable SIBs.

Developing rechargeable Na-CO2 batteries is significant for energy conversion and utilization of CO2 . However, the reported batteries in pure CO2 atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g(-1) . Herein, we realized the rechargeability of a Na-CO2 battery, with the proposed and demonstrated reversible reaction of 3 CO2 +4 Na↔2 Na2 CO3 +C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g(-1) at 1 A g(-1) (≈1000 Wh kg(-1) ) and runs for 200 cycles with controlled capacity of 2000 mAh g(-1) at charge voltage <3.7 V. The porous structure, high electro-conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO2 .

High-performance quasi–solid state Na-CO2 batteries are constructed with polymer electrolyte and a reduced graphene oxide Na anode.

Ultra-thin PTAA layers contribute to interface defect passivation and interface recombination reduction to improve the efficiency of perovskite solar cells.

In this Letter, we report the preparation of sulfur nanodots (2 nm average) electrodeposited on flexible nickel foam and their application as high-performance cathode of Li-S batteries. An electrodepostion method was applied to prepare the cathode at room temperature and the sulfur mass was controllable from 0.21 to 4.79 mg/cm(2) in a large area of over 100 cm(2). The optimized cathode with 0.45 mg/cm(2) S on Ni foam displayed high initial discharge capacity (1458 mAh/g at 0.1 C), high rate capability (521 mAh/g at 10 C), and long cycling stability (895 mAh/g after 300 cycles at 0.5 C and 528 mAh/g after 1400 cycles at 5 C). Moreover, in situ Raman and transmission electron microscopy analysis demonstrated the fundamentals of reversible electrochemical reaction between S and Li2S nanodots. This fast, facile, and one-step cathode preparation method with excellent electrochemical performance will lead to technological advances of S cathode in Li-S batteries.

Developing flexible Li-CO batteries is a promising approach to reuse CO and simultaneously supply energy to wearable electronics. However, all reported Li-CO batteries use liquid electrolyte and lack robust electrolyte/electrodes structure, not providing the safety and flexibility required. Herein we demonstrate flexible liquid-free Li-CO batteries based on poly(methacrylate)/poly(ethylene glycol)-LiClO -3 wt %SiO composite polymer electrolyte (CPE) and multiwall carbon nanotubes (CNTs) cathodes. The CPE (7.14×10 mS cm ) incorporates with porous CNTs cathodes, displaying stable structure and small interface resistance. The batteries run for 100 cycles with controlled capacity of 1000 mAh g . Moreover, pouch-type flexible batteries exhibit large reversible capacity of 993.3 mAh, high energy density of 521 Wh kg , and long operation time of 220 h at different degrees of bending (0-360°) at 55 °C.

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