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Rechargeable potassium metal batteries are promising energy storage devices with potentially high energy density and markedly low cost. However, eliminating dendrite growth and achieving a stable electrode/electrolyte interface are the key challenges to tackle. Herein, a novel "quasi‐liquid" potassium‐sodium alloy (KNA) anode comprising only 3.5 wt% sodium (KNA‐3.5) is reported, which exhibits outstanding electrochemical performance able to be reversibly cycled at 4 mA cm–2 for 2000 h. Moreover, it is demonstrated that adding a small amount of sodium hexafluorophosphate (NaPF6) into the potassium bis(fluorosulfonyl)imide electrolyte allows for the formation of the "quasi‐liquid" KNA on electrode surface. Comprehensive experimental studies reveal the formation of an unusual metastable KNa2 phase during plating, which is believed to facilitate simultaneous nucleation and suppress the growth of dendrites, thereby improving the electrode's cycle lifetime. The "quasi‐liquid" KNA‐3.5 anode demonstrates markedly enhanced electrochemical performance in a full cell when pairing with Prussian blue analogs or sodium rhodizonate dibasic as the cathode material, compared to the pristine potassium anode. Importantly, unlike the liquid KNA reported before, the "quasi‐liquid" KNA‐3.5 exhibits good processability and can be readily shaped into sheet electrodes, showing substantial promise as a dendrite‐free anode in rechargeable potassium metal batteries. [ABSTRACT FROM AUTHOR]

Iron sulfides have been attracting great attention as anode materials for high-performance rechargeable sodium-ion batteries due to their high theoretical capacity and low cost. In practice, however, they deliver unsatisfactory performance because of their intrinsically low conductivity and volume expansion during charge-discharge processes. Here, a facile in situ synthesis of a 3D interconnected FeS@Fe3C@graphitic carbon (FeS@Fe3C@GC) composite via chemical vapor deposition (CVD) followed by a sulfuration strategy is developed. The construction of the double-layered Fe3C/GC shell and the integral 3D GC network benefits from the catalytic effect of iron (or iron oxides) during the CVD process. The unique nanostructure offers fast electron/Na ion transport pathways and exhibits outstanding structural stability, ensuring fast kinetics and long cycle life of the FeS@Fe3C@GC electrodes for sodium storage. A similar process can be applied for the fabrication of various metal oxide/carbon and metal sulfide/carbon electrode materials for high-performance lithium/sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: In order to lower the sintering temperature and shorten firing time, a novel, effective and facile technique has been developed for sintering Yttria-stabilized zirconia (YSZ) electrolyte thin film. Herein this technique, which employs a weak direct current (DC), is used for the first time in the manufacture of the anode-supported solid oxide fuel cell (SOFC). A single cell is directly assembled using a pre-sintered anode/electrolyte and screen printed cathode and subsequently sintered under electric assistance from room temperature to 800 °C at a heating rate of 5 °C min−1. A fully dense YSZ electrolyte film can be observed by scanning electron microscopy (SEM) and the open circuit voltages (OCVs) are in accordance with theoretical values, confirming that the cell possesses a dense YSZ film. Using hydrogen fuel, the maximum power density of this cell was 0.8, 1.1 and 1.4 W cm−2 at 650, 700 and 750 °C, respectively. We believe this DC assisted sintering technique (DC-AST) may not only reduce the cost, but also maintain the anode nanostructure, thus offering a potentially useful manufacturing technique for SOFCs. [Copyright &y& Elsevier]

The ability to directly utilize hydrocarbons and other renewable liquid fuels is one of the most important issues affecting the large scale deployment of solid oxide fuel cells (SOFCs). Herein we designed La 0.2 Sr 0.7 TiO 3 –Ni/YSZ functional gradient anode (FGA) supported SOFCs, prepared with a co-tape casting method and sintered using the field assisted sintering technique (FAST). Through SEM observations, it was confirmed that the FGA structure was achieved and well maintained after the FAST process. Distortion and delamination which usually results after conventional sintering was successfully avoided. The La 0.2 Sr 0.7 TiO 3 –Ni/YSZ FGA supported SOFCs showed a maximum power density of 600 mW cm −2 at 750 °C, and was stable for 70 h in CH 4 . No carbon deposition was detected using Raman spectroscopy. These results confirm the potential coke resistance of La 0.2 Sr 0.7 TiO 3 –Ni/YSZ FGA supported SOFCs. [ABSTRACT FROM AUTHOR]