Improved Stability of Layered and Porous Nickel-Rich Cathode Materials by Relieving the Accumulation of Inner Stress.

The commercial application of high-capacity LiNi0.8 Co0.1 Mn0.1 O2 is impeded by its inferior cycling stability, which has been attributed to structural instability caused by stress accumulation during both calcination and cycling. A porous structure was deliberately introduced into nickel-rich material particles to relieve such stress. Cross-sectional SEM and mercury penetration tests confirmed the successful construction of a porous structure. Ex situ TEM and powder XRD confirmed that the porous structure reduced the stress concentration regions in uncycled nickel-rich material by providing a buffer space. In addition, the porous structure helps the permeation of the electrolyte and alleviates the stress accumulation during cycling, endowing the nickel-rich cathode materials with enhanced rate capability and suppressed phase transition. This strategy can be extended for the synthesis of diverse nickel-rich cathode materials to improve their cycling stability.