Surface modification of positive electrode materials for potassium-ion batteries by atomic layer deposition

Portable electronics and electric vehicles are nowadays powered by Li-ion batteries (LIBs), which combine energy, power, lightweight, and fast charging. The exponential growth of the LIB market is leading to an imbalance between the supply chain and the demand for its resources. In addition to geopolitical concerns related to lithium resources, the use of critical elements in positive electrode materials also raises questions about the environmental impact and long-term development of LIBs. Consequently, there is an urgent need to develop alternative systems to LIBs at the European level, and particularly in France. K-ion batteries (KIBs) would eventually combine several promising features: (i) high energy density (E°(K+/K) = -2.95V vs. SHE), (ii) high power density (high ionic conductivity in organic electrolytes and in Prussian Blue Analogue (PBA) electrode materials), (iii) utilisation of Co- and Ni-free electrode materials, (iv) possible use of Al current collectors at both electrodes, (v) safety during storage and transport (at 0 V), and (vi) possible rapid industrial development.
The objective of this thesis is to develop conformal interface layers with high electronic conductivity and long-term stability directly on positive electrode materials in order to improve stability (life cycle) and optimize the low electronic conductivity of these materials.