A Cation Chelation and Reassembly Route to Synthesize a P2‐type Na0.67Ni0.26Mn0.67Mg0.07O2 Cathode Material for High‐performance Sodium Storage. Issue 11 (27th September 2021) - Xie, Chouwei
Abstract: P2‐type Na2/3 Ni1/3 Mn2/3 O2 (Na‐NM) is an appealing cathode candidate for sodium‐ion batteries (SIBs) but still suffers a fast capacity decay. Mg doping on the Ni‐site in Na‐NM cathode is an effective way to maintain structural stability, but how to achieve the uniform Mg dopant distribution is still a problem. Here, we report a facile cation chelation and reassembly route to prepare one‐dimensional Na0.67 Ni0.26 Mn0.67 Mg0.07 O2 (Na‐NMM) cathode material with uniform element distribution. When evaluated as a cathode material for SIBs, the lower cut‐off voltage could be set to 1.35 V so that an extra reversible capacity of 61 mAh g −1 is contributed from the Mn 4+ /Mn 3+ couple between 2 and 1.35 V, and a total reversible capacity of 173 mAh g −1 is achieved between 4.25 and 1.35 V at 0.1 C. Moreover, the Na‐NMM cathode shows good cycling performance with a reversible capacity of 83 mAh g −1 after 100 cycles at 1 C. Abstract : A cation chelation and reassembly route was developed to synthesize a one‐dimensional Na0.67 Ni0.26 Mn0.67 Mg0.07 O2 cathode material. The uniform doping of Mg 2+ in the cathode material can improve its structural stability and extend its charge/discharge voltage range, thereby achieving a highly reversible capacity and excellent cycling performance.