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

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.