The cycle performance was significantly improved by adding an electrolyte additive in the aqueous electrolyte.

Ni-rich layered cathode materials are considered as promising electrode materials for lithium ion batteries due to their high energy density and low cost. However, the low rate performance and poor electrochemical stability hinder the large-scale application of Ni-rich layered cathodes. In this work, both the rate performance and the structural stability of the Ni-rich layered cathode LiNi0.8Co0.1Mn0.1O2 are significantly improved via the dual-site doping of Nb on both lithium and transition-metal sites, as revealed by neutron diffraction results. The dual-site Nb-doped LiNi0.8Co0.1Mn0.1O2 delivers 202.8 mAh·g–1 with a capacity retention of 81% after 200 electrochemical cycles, which is much higher than that of pristine LiNi0.8Co0.1Mn0.1O2. Moreover, a discharge capacity of 176 mAh·g–1 at 10C rate illustrates its remarkable rate capability. Through in situ X-ray diffraction and electronic transport property measurements, it was demonstrated that the achievement of dual-site doping in the Ni-rich layered cathode can not only suppress the Li/Ni disordering and facilitate the lithium ion transport process but also stabilize the layered structure against local collapse and structural distortion. This work adopts a dual-site-doping approach to enhance the electrochemical performance and structural stability of Ni-rich cathode materials, which could be extended as a universal modification strategy to improve the electrochemical performance of other cathode materials.

Ion conduction refers to a conductive process consisting of the directional motion of ions driven by an electric field, which is one of the most important issues for further improvement of batteries in the current and foreseeable future. In order to better understand the conduction phenomena in alkali metal‐ion (Li+/Na+/K+) batteries (AMIBs) and achieve technological breakthroughs, the recent studies on the ion diffusion of electrode materials and the ion conduction of electrolytes for AMIBs are investigated. Three aspects of the factors that affecting ion conduction in AMIBs are mainly listed: (i) crystal structure related high ion conduction in crystalline materials. (ii) tuning the lattice volume and interface by doping and compounding. (iii) improvement in experimental synthesis and modification methods. Through this review, we hope to facilitate more efficient and targeted research to improve ion conduction in AMIBs.