Abstract
Incremental improvement to the current state-of-the-art lithium-ion technology, for example regarding the physical or electrochemical design, can bridge the gap until the next generation of cells are ready to take Li-ions place. Previously designed two-layered porosity-graded graphite anodes, together with LixNi0.6Mn0.2Co0.2O2 cathodes, were analysed in small pouch-cells with a capacity of around 1 Ah. For comparison, custom-made reference cells with the average properties of two-layered anodes were tested. Ten cells of each type were examined in total. Each cell pair, consisting of one double-layer and one single-layer (reference) cell, underwent the same test procedure. Besides regular charge and discharge cycles, electrochemical impedance spectroscopy, incremental capacity analysis, differential voltage analysis and current-pulse measurement are used to identify the differences in ageing behaviour between the two cell types. The results show similar behaviour and properties at beginning-of-life, but an astonishing improvement in capacity retention for the double-layer cells regardless of the cycling conditions. Additionally, the lifetime of the single-layer cells was strongly influenced by the cycling conditions, and the double-layer cells showed less difference in ageing behaviour.
Highlights
There is a lot of effort put towards the generation of batteries, for example allsolid-state batteries [1] with certain advantages
An example for active material related energy density improvement is the addition of silica into the graphite anode
We investigate the ageing behaviour of lithium-ion pouch-cells based on a common composition—graphite anode, lithium nickel manganese cobalt oxide (NMC)
Summary
There is a lot of effort put towards the generation of batteries, for example allsolid-state batteries [1] with certain advantages. It will still take time until the next-gen technology will potentially replace the current lithium-ion (Li-ion) cells. State-of-the-art Li-ion technology will be the go-to and still have potential to improve Those improvements can include the active material, the electrolyte and the interface in between. An example for active material related energy density improvement is the addition of silica into the graphite anode. An increased electrochemical stability window of the electrolyte can allow for high-energy high-voltage Li-ion cells with different electrode materials [3]. Li-ion systems could be considered the first commercial hybrid solid–liquid batteries (HySolLiq)
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