Utilizing Magnetic‐Field Modulation to Efficiently Improve the Performance of LiCoO2||Graphite Pouch Full Batteries

Abstract

AbstractThe present lithium‐ion battery technology competition almost focuses on finding new materials, while less effort is invested in electrode engineering improvement with low‐cost. This study proposes a simple method of modulating the preferred orientation of crystal phases in LiCoO2 electrode using a ≈500 mT magnetic‐field, cheaply and efficiently improving the performance of LiCoO2||graphite pouch full batteries, including cycling stability, rate performance, and thermal safety performance. Under 3.0 C and 45 °C strict test conditions, LiCoO2‐M⊥||graphite battery even outputs the capacity retention rate of 42.8% after 1000 cycles, while that of pure‐LiCoO2 battery is only 4.4%. Especially, the thermal runaway temperature of the battery needling experiment decreases by considerable 7.7 °C after magnetic‐field modulation. Comprehensive characterizations reveal that vertical magnetic field causes spin alignment of LiCoO2 crystals along the (003) direction. This arrangement effectively improves the Li+ diffusion dynamic and the interface compatibility of the electrode, suppressing the electrode polarization. During the cycling processes, the preferred orientation of LiCoO2 particles forms an enhanced conductive network due to the formation of cross‐linked “Li+ poor regions” on the surface, ultimately achieving significant performance improvement. This work can provide a potential low‐cost strategy for the production of commercial lithium‐ion batteries.