Developing multicomponent transition-metal phosphides has become an efficient way to improve the capacitive performance of single-component transition-metal phosphides. However, reports on quaternary phosphides for supercapacitor applications are still scarce. Here, we report high capacity and energy density of Zn−Ni−Co−P quaternary phosphide nanowire arrays on nickel foam (ZNCP-NF) composed of highly conductive metal-rich phosphides as an advanced binder-free electrode in aqueous asymmetric supercapacitors. In a three-electrode system using the new electrode, a high specific capacity of 1111 C g −1 was obtained at a current density of 10 A g −1 . Analysis of this aqueous asymmetric supercapacitor with ZNCP-NF as the positive electrode and commercial activated carbon as the negative electrode reveals a high energy density (37.59 Wh kg −1 at a power density of 856.52 W kg −1 ) and an outstanding cycling performance (capacity retention of 92.68% after 10 000 cycles at 2 A g −1 ). Our results open a path for a new design of advanced electrode material for supercapacitors.

Electrolyte engineering via fluorinated additives is promising to improve cycling stability and safety of high‐energy Li‐metal batteries. Here, an electrolyte is reported in a porous lithium fluoride (LiF) strategy to enable efficient carbonate electrolyte engineering for stable and safe Li‐metal batteries. Unlike traditionally engineered electrolytes, the prepared electrolyte in the porous LiF nanobox exhibits nonflammability and high electrochemical performance owing to strong interactions between the electrolyte solvent molecules and numerous exposed active LiF (111) crystal planes. Via cryogenic transmission electron microscopy and X‐ray photoelectron spectroscopy depth analysis, it is revealed that the electrolyte in active porous LiF nanobox involves the formation of a high‐fluorine‐content (>30%) solid electrolyte interphase layer, which enables very stable Li‐metal anode cycling over one thousand cycles under high current density (4 mA cm−2). More importantly, employing the porous LiF nanobox engineered electrolyte, a Li || LiNi0.8Co0.1Mn0.1O2 pouch cell is achieved with a specific energy of 380 Wh kg−1 for stable cycling over 80 cycles, representing the excellent performance of the Li‐metal pouch cell using practical carbonate electrolyte. This study provides a new electrolyte engineering strategy for stable and safe Li‐metal batteries.

Currently, developing high voltage (beyond 2 V) rechargeable Mg-ion batteries still remains a great challenge owing to the limit of corrosive electrolyte and low compatibility of anode material. Here we report a facile one step solid state alloying route to synthesize nanoclustered MgBi alloy as a high-performance anode to build up a 2 V Mg-ion battery using noncorrosive electrolyte. The fabricated nanoclustered MgBi anode delivers a high reversible specific capacity (360 mAh g) with excellent stability (90.7% capacity retention over 200 cycles) and high Coulombic efficiency (average 98%) at 0.1 A g. The good performance is attributed to the stable nanostructures, which effectively accommodate the reversible Mg ion insertion/deinsertion without losing electric contact among clusters. Significantly, the nanoclustered MgBi anode can be coupled with high voltage cathode Prussian Blue to assemble a full cell using noncorrosive electrolyte, showing a stable cycling (88% capacity retention over 200 cycles at 0.2 A g) and good rate capability (103 mAh g at 0.1 A g and 58 mAh g at 2 A g). The energy and power density of the as-fabricated full cell can reach up to 81 Wh kg and 2850 W kg, respectively, which are both the highest values among the reported Mg-ion batteries using noncorrosive electrolytes. This study demonstrates a cost-effective route to fabricate stable and high voltage rechargeable Mg-ion battery potentially for grid-scale energy storage.