High‐Performance Lithium‐ion Supercapatteries Constructed Using Li 3 V 2 (PO 4 ) 3 /C Mesoporous Nanosheets

Ru- and Cl-Codoped Li3 V2 (PO4 )3 with Enhanced Performance for Lithium-Ion Batteries in a Wide Temperature Range

Li₃ V₂ (PO₄ )₃ (LVP) is a promising cathode material for lithium-ion batteries, especially when used in a wide temperature range, due to its high intrinsic ionic mobility and theoretical capacity. Herein, Ru- and Cl-codoped Li₃ V₂ (PO₄ )₃ (LVP-Ru_x -Cl_{3 x} ) coated with/without a nitrogen-doped carbon (NC) layer are synthesized. Among them, the optimized sample (LVP-Ru_0.05 -Cl_0.15 @NC) delivers remarkable performances at both room temperature and extreme temperatures (-40, 25, and 60 °C), indicating temperature adaptability. It achieves intriguing capacities (49 mAh g^-1 at -40 °C, 128 mAh g^-1 at 25 °C, and 123 mAh g^-1 at 60 °C, all at 0.5 C), long cycle life (94% capacity retention after 2000 cycles at 25 °C and 5 C), and high-rate capabilities (up to 20 C). The structural evolution features and capacity loss mechanisms of LVP-Ru_0.05 -Cl_0.15 @NC are further investigated using in situ X-ray diffraction (XRD) at different temperatures (-10, 25, and 60 °C) during redox reactions. Theoretical calculations elucidate that Ru- and Cl-codoping can greatly improve the intrinsic diffusion coefficient of LVP by reducing its bandgap energy and lowering the energy barrier of lithium-ion diffusion. In "all-weather" conditions, the dual-element co-doping strategy is critical for increasing electrochemical performance.

Na0.76V6O15@Boron Carbonitride Nanotube Composites as Cathodes for High-Performance Lithium-Ion Capacitors

Lithium-ion capacitors (LICs) are considered one of the most promising new-generation energy storage devices because they combine the advantages of lithium-ion batteries and supercapacitors. However, the widely used commercial carbon cathode greatly limits the electrochemical performance of existing LICs due to its limited specific capacity. Improving the specific capacity of the cathode is one of the keys to solving this problem. To this end, the Na0.76V6O15 (NaVO)@boron carbonitride nanotube (BCNNT) cathode has been successfully synthesized via a facile solid phase reaction and hydrothermal reaction followed by annealing. Benefitting from the synergy between the high conductivity of BCNNTs and the high capacity of NaVO, the NaVO@BCN cathode exhibits excellent capacity and good cyclic stability. A LIC was assembled by a prefabricated NaVO@BCN cathode and a prelithiated commercial hard carbon (HC) anode. Notably, the NaVO@BCN−1//HC LIC delivered an energy density of 238.7 Wh kg−1 at 200 W kg−1 and still delivered 81.9 Wh kg−1 even at 20 kW kg−1. Therefore, our strategy provides a novel idea for designing high-performance LICs.

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

Lithium-ion capacitors (LICs) are emerging as one of the most advanced energy storage devices by combining the virtues of both supercapacitors (SCs) and lithium-ion batteries (LIBs). However, the kinetic and capacity mismatch between anode and cathode is the main obstacle to wide applications of LICs. Therefore, the effective strategy of constructing a high-performance LIC is to improve the rate and cycle performance of the anode and the specific capacity of the cathode. Herein, the nickel cobalt phosphate (NiCoP) microspheres anode is demonstrated with robust structural integrity, high electrical conductivity, and fast kinetic feature. Simultaneously, the watermelon-peel biomass-derived carbon (WPBC) cathode is demonstrated a sustainable synthesis strategy with high specific capacity. As expected, the NiCoP exhibits high specific capacities (567 mAh g^-1 at 0.1 A g^-1), superior rate performance (300 mAh g^-1 at 1A g^-1), and excellent cycle stability (58 mAh g^-1 at 5 A g^-1 after 15,000 cycles). The WPBC possesses a high specific surface area (SSA) of 3303.6 m² g^-1 and a high specific capacity of 226 mAh g^-1 at 0.1 A g^-1. Encouragingly, the NiCoP//WPBC-6 LIC device can deliver high energy density (ED) of 127.4 ± 3.3 and 67 ± 3.8Wh kg^-1 at power density (PD) of 190 and 18240 W kg^-1 (76.4% capacity retention after 7000 cycles), respectively.