Operando XRD study on the Effect of Boron Doping on the Failure Mechanisms of Na-, Ni- and Mn-based Positive Electrodes in Sodium-Ion Batteries

Layered oxides have emerged as one of the most promising candidates for high capacity positive electrode materials in sodium-ion batteries (SIB). It has been demonstrated that Na, Ni and Mn-based layered oxide materials are relatively sustainable in terms of their composition, and high capacities have been achieved. However, it has been noted that at higher voltages, the crystal structure of these materials tends to degrade during cycling1,2. Doping the electrode with different transition metals such as Fe, Mg, Ti etc., has been an immensely popular strategy to avoid this degradation3–5. However, there has been little attention on doping with lighter electrochemically inactive elements such as boron that do not lower the materials' theoretical capacity.