Addressing Unfavorable Influence of Particle Cracking with a Strengthened Shell Layer in Ni-Rich Cathodes

Ni-rich layered materials are widely accepted as pivotal cathode materials to realize low-cost high-energy-density batteries. However, they still suffer from the intrinsic mechanically induced degradation due to the large lattice deformation. Here, we fabricate a strengthened shell layer on polycrystalline secondary particles to address the unfavorable influence of particle cracking instead of suppressing their bulky pulverization. This tough layer, constructed via welding LiNi_0.8Co_0.1Mn_0.1O₂ primary particles with a Nb-based ceramic, increases Young's modulus of the particles 2.6 times. This layer allows the particles work properly with the intact spherical morphology even after bulk cracking. It seems that this tough skin stops the bulky flaws growing into perforated fissures and keeps the electrodes from quick polarization. This approach demonstrates that, besides addressing the intrinsic challenges directly, appropriate particle engineering is another efficient way to exploit the potentials of Ni-rich cathodes and power batteries made out of them.