Material Optimization Engineering toward xLiFePO4·yLi3V2(PO4)3 Composites in Application-Oriented Li-Ion Batteries

Abstract

The development of LiFePO4 (LFP) in high-power energy storage devices is hampered by its slow Li-ion diffusion kinetics. Constructing the composite electrode materials with vanadium substitution is a scientific endeavor to boost LFP’s power capacity. Herein, a series of xLiFePO4·yLi3V2(PO4)3 (xLFP·yLVP) composites were fabricated using a simple spray-drying approach. We propose that 5LFP·LVP is the optimal choice for Li-ion battery promotion, owning to its excellent Li-ion storage capacity (material energy density of 413.6 W·h·kg−1), strong machining capability (compacted density of 1.82 g·cm−3) and lower raw material cost consumption. Furthermore, the 5LFP·LVP||LTO Li-ion pouch cell also presents prominent energy storage capability. After 300 cycles of a constant current test at 400 mA, 75% of the initial capacity (379.1 mA·h) is achieved, with around 100% of Coulombic efficiency. A capacity retention of 60.3% is displayed for the 300th cycle when discharging at 1200 mA, with the capacity fading by 0.15% per cycle. This prototype provides a valid and scientific attempt to accelerate the development of xLFP·yLVP composites in application-oriented Li-ion batteries.

Synergy and Symbiosis Analysis of Capacity-Contributing Polypyrrole and Carbon-Coated Lithium Iron Phosphate Nanostructures for High-Performance Cathode Materials

“…During the recent decades, lithium-ion batteries (LIBs) have played an indispensable role in energy storage for portable electronics and electric vehicles with large capacities, high energy density, and output voltages. − In lithium-ion batteries, four important components are involved, cathode, anode, electrolyte, and separator, in which the cathode currently limits the energy density and dominates the battery cost. The current popularly applied commercial cathode materials for lithium-ion batteries include lithium nickel cobalt manganese oxides (NCM) , and olivine-type lithium iron phosphate (LFP). − However, how to improve theoretical capacity, rate performance, structural instability, electronic conductivity, and Li + transfers is always challenging for researchers to develop high-performance, low-cost, and high-safety cathode materials. , Extensive efforts have been made to circumvent these drawbacks, such as carbon coating, conductive agent hybridizing, element doping, and particle size reduction. , Nevertheless, these modifying strategies from an inorganic perspective always meet some new problems. For example, common ionic/electronic conductive additives are usually electrochemically inactive, which decrease the energy density of batteries.…”