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NANO2021-Nanoteknologi og nye materiale

Stabilising Conversion Anodes with Solid Molecular Ionic Composite Electrolytes for Solid State Lithium Ion Batteries (SMICE-Li)

Alternative title: Stabilisering av konverterende type anoder med fast molekylær ionisk komposittelektrolytter for faststoff litiumionbatterier

Awarded: NOK 4.3 mill.

The SMICE-Li project seeks to improve two components of current generation lithium-ion batteries: The anode and the electrolyte. The project will concentrate on developing alternative types of anode materials known as "conversion-alloy electrodes" and pairing them with a completely new type of electrolyte known as a Solid Molecular Ionic Composite (SMICE). A SMICE is a mixture of a stiff polymer molecule with an Ionic Liquid, with properties that can be quite easily tuned so that they can have characteristics of both liquid- and solid- electrolytes. The conversion-alloy electrodes will be nano-structured metal oxides made by industrially scalable synthesis methods and will be based on elements such as iron and tin, which are abundant in nature. These can offer up to 2.5x the capacity of graphite anodes, without the safety concerns that accompany the use of lithium metal. The major challenge using conversion and alloy type electrodes is that the reactions occurring during use are extremely complex (much more so than graphite). Conversion electrode materials function as extreme nanoscale composites which are formed on initial charging from reactions between the anode material and components in the electrolyte. It is thus important to understand how these form in order to control and optimise performance. The project will begin with the synthesis and evaluation of new anode and SMICE materials by SINTEF (Norway) and the National Research & Development Institute for Cryogenics and Isotopic Technologies (Romania), with nano-structural characterisation performed at Institut Charles Gerhardt de Montpellier. The anodes and SMICEs will be developed together as a combined system, with computer modelling (SINTEF) assisting in understanding the complex reactions occurring during battery cycling. At the end of the project a Solid State Battery with capacity comparable to current state of the art is hoped to be demonstrated.

The SMICE-Li project is an ambitious proposal to demonstrate a completely novel Solid State Battery (SSB) concept based on a Conversion Anode Material (CAM) coupled with a Solid Molecular Ionic Composite Electrolyte (SMICE) electrolyte and a state of the art high voltage (HV) cathode. The project will focus on the parallel development of new oxide-based CAM materials based on complex composition transition metal oxides and on developing new SMICE-type electrolytes. The use of CAM anode materials offers the prospect of greatly increased capacities relative to current generation graphite anodes whilst addressing the difficulties surrounding lithium metal electrode manufacturing (air sensitivity, thickness control, and excess inventory lithium), and the challenges with controlled plating during cycling. The SMICE electrolytes combine the advantages of ionic liquids (safety, voltage and thermal stability) with the mechanical advantages of solid polymer electrolytes and the high ionic conductivity of a liquid electrolyte. State of the art operando spectroscopies and local structure analyses will guide development via fundamental understanding of interphase chemistries, which are critical to battery performance and lifetime. Central to the SMICE-Li project is that development be driven by fundamental understanding. DFT modelling approaches will be used to guide anode materials synthesis via the prediction of entropy-stabilised oxide phases, and will also assist in the interpretation of the operando spectroscopic investigations of local structures and interface chemistries, which will in turn guide the development and selection of materials for combination in a SSB. The ultimate goal of the project is to demonstrate a Solid State Battery comprising CAM anode, SMICE electrolyte and a high voltage cathode, with a specific energy density in excess of 300Wh/kg and a cycle life in excess of 200 cycles.

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NANO2021-Nanoteknologi og nye materiale