Designing Cathode Materials and Composite Electrolytes for Li-ion Batteries and Beyond

Li-rich layered oxides (LRLOs) are ones of the most promising cathode materials for next generation high-energy-density lithium-ion batteries (LIBs) because of their extraordinary specific capacity over 250 mA h/g. Such high capacity originates from the “activation” of Li from transition metal layer in the Li₂MnO₃ phase. However, the activation process is kinetically slow, and the relevant phase transformation as well as the electrode /electrolyte side reactions at high voltage region cause serious capacity and voltage decay. In this talk, we present our recent studies on the electrochemical activation mechanism and capacity/voltage decay challenges. A series of <i>ex-situ</i> and <i>in-situ</i> characterisations reveal the structural evolution mechanism of the cathode materials, and the optimised materials deliver a high capacity of ~270 mA h/g and with good capacity retention of &gt;98% over 300 cycles. We will also discuss our recent works on the atomic layer protection of a new high-voltage cathode material with excellent cycling stability of over 1000 cycles, the design of integrated printable solid-state battery systems for flexible electronics, and the development of new gradient composite electrolytes for solid-state sodium ion batteries.