Realizing high-performance and low-cost lithium-ion capacitor by regulating kinetic matching between ternary nickel cobalt phosphate microspheres anode with ultralong-life and super-rate performance and watermelon peel biomass-derived carbon cathode

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.

Recent Advances in Functionalized Biomass-Derived Porous Carbons and their Composites for Hybrid Ion Capacitors

Hybrid ion capacitors (HICs) have aroused extreme interest due to their combined characteristics of energy and power densities. The performance of HICs lies hidden in the electrode materials used for the construction of battery and supercapacitor components. The hunt is always on to locate the best material in terms of cost-effectiveness and overall optimized performance characteristics. Functionalized biomass-derived porous carbons (FBPCs) possess exquisite features including easy synthesis, wide availability, high surface area, large pore volume, tunable pore size, surface functional groups, a wide range of morphologies, and high thermal and chemical stability. FBPCs have found immense use as cathode, anode and dual electrode materials for HICs in the recent literature. The current review is designed around two main concepts which include the synthesis and properties of FBPCs followed by their utilization in various types of HICs. Among monovalent HICs, lithium, sodium, and potassium, are given comprehensive attention, whereas zinc is the only multivalent HIC that is focused upon due to corresponding literature availability. Special attention is also provided to the critical factors that govern the performance of HICs. The review concludes by providing feasible directions for future research in various aspects of FBPCs and their utilization in HICs.

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.

Freestanding trimetallic Fe-Co-Ni phosphide nanosheet arrays as an advanced electrode for high-performance asymmetric supercapacitors

Transition metal phosphides hold great promise for high performance battery-type electrode materials due to their superb electrical conductivity and high theoretical capacity. Unfortunately, the electrochemical properties of single metal or bimetallic phosphides are unsatisfactory owing to their low energy density and poor cyclic stability, and one feasible approach is to introduce heteroatoms to form trimetallic phosphides. Here, novel Fe-Co-Ni-P nanosheet arrays are in situ synthesized on a flexible carbon cloth substrate via an electrodeposition method followed by a phosphorization treatment. Due to the presence of abundant redox active sites, large specific surface area with mesoporous channels, desirable electrical conductivity, modified electronic structure, and synergistic effect of Fe, Co, and Ni ions, the as-prepared Fe-Co-Ni-P electrode displays significantly enhanced electrochemical performance when compared to bimetallic phosphides Fe-Co-P and Fe-Ni-P. Remarkably, the Fe-Co-Ni-P electrode exhibits a large specific capacity of 593.0 C g^-1 at 1 A g^-1, exceptional rate performance (80.3% capacity retention at 20 A g^-1), and good cycling stability (84.2% capacity retention after 5000cycles). Besides, an asymmetric supercapacitor device with Fe-Co-Ni-P electrode as a positive electrode and a hierarchical porous carbon as a negative electrode shows a high energy density of 57.1 Wh kg^-1 at a power density of 768.5 W kg^-1 as well as excellent cyclability with 88.4% of initial capacity after 10,000cycles. This work manifests that the construction of trimetallic phosphides is an effective strategy to solve the shortcomings of single or bimetallic phosphides for high-performance supercapacitors.