Research and development of flexible lithium-ion batteries (LIBs) with high energy density and long cycle life for portable and wearable electronic devices has been a cutting-edge effort in recent years. In this paper, a novel flexible self-standing anode for LIBs is fabricated successfully, in which NiCoP nanowires (NWs) coated with FeCoP nanosheets (NSs) to form core–shell heterostructure arrays are grown on carbon cloth (CC) (designated as NiCoP-NWs@FeCoP-NSs/CC). The obtained NiCoP-NWs@FeCoP-NSs/CC anode integrates the merits of the one-dimensional (1D) NiCoP-NW core and two-dimensional (2D) FeCoP-NS shell and the CC to show a high lithium-ion storage capacity with long-term cycling stability (1172.6 mA h g−1 at 1 A g−1 up to 300 cycles with a capacity retention of 92.6%). The kinetics studies demonstrate that the pseudocapacitive behavior dominates the fast lithium storage of this anode material. For fundamental mechanistic understanding, density functional theory (DFT) analysis is carried out, and manifests that electronic synergy can boost the superior performance of the NiCoP-NWs@FeCoP-NSs/CC anode. The assembled LiFePO4//NiCoP-NWs@FeCoP-NSs/CC full battery gives a discharge capacity of 469.9 mA h g−1 at 0.5 A g−1 after 500 cycles, and even at 2 A g−1, it still can retain 581.5 mA h g−1. Besides, the soft pack full battery can keep the LED lit continuously when it is folded at different angles and maintain brightness for a period of time, highlighting the large application potential of this flexible LIB for wearable electronic devices. This work provides an idea for the design and construction of advanced metal phosphide flexible electrodes for LIBs.
Jinghui Shi,Fen Qiu,Wenbo Yuan,Manman Guo,Zhang-Hui Lu
Designing efficient non-precious electrocatalysts to facilitate overall water splitting is crucial and highly desirable but remains challenging. In this study, we synthesized nitrogen-doped carbon-decorated CoP@FeCoP yolk-shelled micro-polyhedras (denoted as CoP@FeCoP/NC YSMPs) via the phosphorization of ZIF-67@Co-Fe Prussian blue analogues YSMPs. The yolk-shelled construction and nitrogen-doped carbon matrix can effectively reduce the degree of CoP agglomeration, which is beneficial for increasing the specific surface area and active sites of the catalysts. The synergistic effect of yolk-shelled structure and nigtrogen-doped carbon matrix also optimizes the electronic structure and enhances the electrocatalytic activity of CoP@FeCoP/NC YSMPs. In an alkaline electrolyte, the overpotentials of hydrogen evolution reaction and oxygen evolution reaction only need 141 and 238 mV, respectively, to drive the current density of 10 mA cm −2 . When a two-electrode water splitting device was conducted with the as-prepared catalyst, it required only a low cell voltage of 1.68 V to achieve a current density of 10 mA cm −2 and displayed outstanding stability over 20 h. This work offers insights into the facile, controllable synthesis strategy of various non-precious metal nanomaterials for high-efficiency water splitting electrocatalysis.
Yingping Zheng,Dehua Yu,Wei Xu,Ke Zhang,Kaili Ma,Xinyu Guo,Yongbing Lou,Mulin Hu
Electrochemical water splitting is a potential green hydrogen energy generation technique. With the shortage of fresh water, abundant seawater resources should be developed as the main raw material for water electrolysis. However, since the precipitation reaction of chloride ions in seawater will compete with the oxygen evolution reaction (OER) and corrode the catalyst, seawater electrolysis is restricted by the decrease in activity, low stability, and selectivity. Rational design and development of efficient and stable catalysts is the key to seawater electrolysis. Herein, a high-activity bimetallic phosphide FeCoP, grown on a reduced graphene oxide (rGO)-protected Ni Foam (NF) substrate using FeCo Prussian Blue Analogue (PBA) as a template, was designed for application in alkaline natural seawater electrolysis. The OER activity confirmed that the formed FeCoP@rGO/NF has high electrocatalytic performance. In 1 M KOH and natural alkaline seawater, the overpotential was only 257 mV and 282 mV under 200 mA cm−2, respectively. It also demonstrated long-term stability up to 200 h. Therefore, this study provides new insight into the application of PBA as a precursor of bimetallic phosphide in the electrolysis of seawater at high current density.
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