Ni‐rich cathodes with superior energy densities have spurred extensive attention for lithium‐ion batteries (LIBs), whereas their commercialization is hampered by structural degradation, thermal runaway, and dramatic capacity fading. Herein, boron (B) with high binding energy to oxygen (O) is gradiently incorporated into each primary particle and piezoelectric Li2B4O7 (LBO) is homogeneously deposited on the secondary particles of polycrystalline LiNi0.8Co0.1Mn0.1O2 (NCM811) surface through a facile in situ construction strategy, intending to synchronously enhance electrochemical stabilities and Li+ kinetics upon cycling. Particularly, the as‐obtained LBO modified NCM811 cathode exhibits an excellent capacity retention (88.9% after 300 cycles, 1 C) and rate performance (112.2 mAh g−1, 10 C) with Li metal anode, the NCM811‐LBO/Li4Ti5O12 full cell achieves a capacity retention of 92.6% after 1000 cycles (0.5 C). Intensive explorations in theoretical calculation, multi‐scale in/ex situ characterization and finite element analysis ascertain that the improvement mechanism of LBO modification can be attributed to the synergistic contributions of rational designed O release buffer and interface cation self‐accelerator. This study provides a facile and practical method to prevent structural degradation and thermal runaway for high‐energy LIBs.

Ni‐rich cathodes with high energy densities are considered as promising candidates for advanced lithium‐ion batteries, whereas their commercial application is in dilemma due to dramatic capacity decay and poor structure stability stemmed from interfacial instability, structural degradation, and stress–strain accumulation, as well as intergranular cracks. Herein, a piezoelectric LiTaO3 (LTO) layer is facilely deposited onto Li[NixCoyMn1−x−y]O2 (x = 0.6, 0.8) cathodes to induce surface polarized electric fields via the intrinsic stress–strain of Ni‐rich active materials, thus modulating interfacial Li+ kinetics upon cycling. Various characterizations indicate that the electrochemical performances of LTO‐modified cathodes are obviously enhanced even under large current density and elevated temperature. Intensive explorations from in situ X‐ray diffraction technique, finite element analysis, and first‐principle calculation manifest that the improvement mechanism of LTO decoration can be attributed to the enhanced structural stability of bulk material, suppressed stress accumulation, and regulated ion transportation. These findings provide deep insight into surface coupling strategy between mechanical and electric fields to regulate the interfacial Li+ kinetics behavior and enhance structure stability for Ni‐rich cathodes, which will also arouse great interest from scientists and engineers in multifunctional surface engineering for electrochemical systems.

Poor thermal stability and severe structural degradation of Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode during the (de)lithiation process hinder its further application. As a typical thermal barrier material and ion conductor, La2Zr2O7 (LZO) was herein served as the multifunctional modification layer due to its excellent thermal stability, robust chemical stability, and prominent Li+ conductivity. Through optimizing the contents of LZO, 2 wt.% LZO-coated NCM622 (2LZO-NCM) displayed the much improved cycling stability (66.0% capacity retention at 0.2 °C after 300 cycles at 55 °C) and rate capability (73.0 mAh g−1 at 5 °C) as compared with the pristine NCM622 (59.3%, 22.4  mAh g−1). An aging test, differential scanning calorimetry research, and kinetics analysis were conducted to unveil the improvement mechanism of electrochemical performances for 2LZO-NCM, mainly owing to the relieved structure degradation, boosted thermal stability, and enhanced electrochemical kinetics after LZO modification, synergistically contributing to the improved electrochemical performances. This work provides a universal avenue to enhance the thermal stability and electrochemical performances of the NCM622 cathode via employing the thermal barrier material as a coating layer, even in other cathodes beyond NCM622.