In this project, the first step will be the synthesis of layered alkali transition metal compounds and the evaluation of their electrochemical behavior as electrode materials in rechargeable batteries (lithium-ion mainly, but other alkali-ion systems are possible). From that structural and magnetic characterization could be already performed by analyzing ex situ targeted compositions obtained along the electrochemical cycling. This task will be carried out at Institut Charles Gerhardt de Montpellier (ICGM) and should last at least 1 year. Then the use of neutron diffraction represents the second step of the investigation, and it will be performed at Institut Laue Langevin (ILL) at Grenoble. On the most promising materials obtained before, ex situ analysis could be performed at various temperatures to access to both the structural and the magnetic structures, and also operando experiment to collect an general overview of the structural transitions. This task should last 2 years. The originality of this project is the important part of neutron, coupled with laboratory X-ray diffraction, this technique could access to useful structural information regarding alkali/vacancy ordering or could discriminate between two elements when alkali-mixed compositions are investigated. In addition, neutron diffraction can access to the magnetic structure and could then be correlated to magnetic measurements. Ideally, operando analysis will be preferred to picture all the structural transition. Besides ILL, the project will also take place at Institut Charles Gerhardt (Montpellier) to perform the synthesis of the materials, and the electrochemical and magnetic investigations, with supporting of DFT calculations in relevant cases.