Ni2P/graphitic carbon nanostructure electrode with superior electrochemical performance

Hierarchical Phosphide-Based Hybrid Anodes for High-Performance Lithium-Ion Batteries

Transition metal phosphides (TMPs) have emerged as promising anode materials for lithium-ion batteries (LIBs). However, their poor intrinsic conductivity and significant volume changes result in slow redox kinetics and structural collapse during cycling, which hinder their practical application. Here, a hierarchical hybrid anode is synthesized by evenly dispersing Ni2P particles with N-doped carbon encapsulation on Co(OH)2 nanosheets (Co(OH)2/Ni2P@N-C). This distinctive hybrid structure enhances electron/ion conductivity and reduces the Li+ transport distance, thereby boosting LIB performance. The hierarchical Co(OH)2/Ni2P@N-C hybrid anode delivers a high reversible capacity of 610 mAh g-1 at 0.05 A g-1 and exhibits exceptional long-term stability. This approach could pave the way for the development of high-performance LIBs and provide crucial guidance for designing high-energy-density anodes based on TMPs.

State-of-the-Art Two-Dimensional Metal Phosphides for High Performance Lithium-ion Batteries: Progress and Prospects

Lithium-ion batteries (LIBs) with high energy density, long cycle life and safety have earned recognition as outstanding energy storage devices, and have been used in extensive applications, such as portable electronics and new energy vehicles. However, traditional graphite anodes deliver low specific capacity and inferior rate performance, which is difficult to satisfy ever-increasing demands in LIBs. Very recently, two-dimensional metal phosphides (2D MPs) emerge as the cutting-edge materials in LIBs due to their overwhelming advantages including high theoretical capacity, excellent conductivity and short lithium diffusion pathway. This review summarizes the up-to-date advances of 2D MPs from typical structures, main synthesis methods and LIBs applications. The corresponding lithium storage mechanism, and relationship between 2D structure and lithium storage performance is deeply discussed to provide new enlightening insights in application of 2D materials for LIBs. Several potential challenges and inspiring outlooks are highlighted to provide guidance for future research and applications of 2D MPs.

A Metal-Organic Framework-Derived Strategy for Constructing Synergistic N-Doped Carbon-Encapsulated NiCoP@N-C-Based Anodes toward High-Efficient Lithium Storage

Transition metal phosphides (TMPs) have been regarded as the prospective anodes for lithium-ion batteries (LIBs). However, their poor intrinsic conductivity and inevitable large volume variation result in sluggish redox kinetics and the collapse of electrode structure during cycling, which substantially hinders their practical use. Herein, an effective composite electrodes design strategy of "assembly and phosphorization" is proposed to construct synergistic N-doped carbon-encapsulated NiCoP@N-C-based composites, employing a metal-organic frameworks (MOFs) as sacrificial hosts. Serving as the anodes for LIBs, one representative P-NCP-NC-600 electrode exhibits high reversible capacity (858.5 mAh g-1 , 120 cycles at 0.1 A g-1 ) and superior long-cycle stability (608.7 mAh g-1 , 500 cycles at 1 A g-1 ). The impressive performances are credited to the synergistic effect between its unique composite structure, electronic properties and ideal composition, which achieve plentiful lithium storage sites and reinforce the structural architecture. By accompanying experimental investigations with theoretical calculations, a deep understanding in the lithium storage mechanism is achieved. Furthermore, it is revealed that a more ideal synergistic effect between NiCoP components and N-doped carbon frameworks is fundamentally responsible for the realization of superb lithium storage properties. This strategy proposes certain instructive significance toward designable high-performance TMP-based anodes for high-energy density LIBs.

Metal-organic framework derived inverse opal type 3D graphitic carbon for highly stable lithium-ion batteries

Graphitic carbon-based anodes for lithium-ion batteries have seen remarkable development and commercial acceptance during the past three decades. Still, the performance of these materials is limited due to the low surface area, stacking of layers, poor porosity, and meager conductivity. To overcome these limitations, we propose using polystyrene as a core and small-sized zeolitic imidazolate framework-67 (ZIF-67) particles as decorators to develop a highly porous three-dimensional graphitic carbon material. The developed material is optimized with the carbonization temperature for the best anodic performance of LIBs. The pyridinic nitrogen content in the material carbonized at 700 °C makes it high performing and more stable than the samples treated at 600, 800, and 900 °C. The packed coin cell exhibited an initial discharge capacity of 775 mA h g-1 at a current density of 50 mA g-1, which increases to 806 mA h g-1 after testing the material at different current densities for 55 cycles. The packed half-cell exhibited a highly stable performance of about 96% even after testing for 2000 cycles at 1 A g-1.

Electronic synergy to boost the performance of NiCoP-NWs@FeCoP-NSs anodes for flexible lithium-ion batteries

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.

Enhanced electrochemical performance of MoS2/graphene nanosheet nanocomposites

Molybdenum disulfide (MoS2) is attractive as an anode material for next-generation batteries, because of its layered structure being favorable for the insertion/deinsertion of Li+ ions, and its fairly high theoretical capacity. However, since the MoS2 anode material has exhibited disadvantages, such as low electrical conductivity and poor cycling stability, to improve the electrochemical performance of MoS2 in this study, a nanocomposite structure consisting of MoS2 and GNS (MoS2/GNS) as an anode for LIBs was prepared, by controlling the weight ratios of MoS2/GNS. The X-ray diffraction patterns and electron microscopic analysis showed that the nanocomposite electrode structure consisted of well-formed MoS2 nanoparticles and GNS. Compared to MoS2-only, the MoS2/GNS composites exhibited high retention and improved capacity at high current densities. In particular, among these nanocomposite samples, MoS2/GNS(8 : 2) with an appropriate portion of GNS exhibited the best LIB performance, due to the lowest interfacial resistance and highest Li-ion diffusivity.