CONTEXT

There are currently some discussion about Li-ion battery especially related to their cost. Raw lithium material costs is almost multiply by 2 since the first Li-ion battery in 1991 and is still increasing due to the market demand. In addition there is some concern about the lithium ressource which is located only in a few places and which could not cope with the dramatically increasing demand due to auomotive transportation and grid related applications.
Na-ion batteries could become an alternative thank to the better availability of Na and the lower cost of its precursors.
Lot of work was dedicated to cathode material but graphite whch is widely used as anode, is not as suitable as for Li due to the size difference of ionic radius of Na ion (>55% Li-ion).
Current material such as hard carbon or even Sb are not satisfactory. Hard carbon exhibits a capacity fading due to passivation layer onto the carbon surface.

TECHNICAL DESCRIPTION

In the present work, the inventors have developped a new anodic material for Na-ion with no toxic element, no rare element and with good electrochemical performance.
These new intermetallic materials exhibit better performances in Na-ion battery than in the same Li-ion equivalent despites an important increase in volume during cycling. In addition, due to a higher potentiel for Na⁺/Na than for Li⁺/Li, the problem of electrolyte degradation at the electrode surface is greatly reduced.

Best performances were obtained with NiP₃ material which exhibit a reversible specific capacity at the 1^st cycle of 1050 mAh/g at C rate with a 99% coulombic efficiency. Cycling results are given hereunder:

« NiP₃ a promisingnegative electrode for Li- and Na-ion batteries » J. Mater. Chem. A, 2014, 2, 2050–2059

BENEFITS

Low cost precursor materials
Availibility of sodium
Good electrochemical properties in swadgelok or coin cell tests
No need of high temperature such as in Zebra type batteries

DEVELOMENT STAGE

Suitable process for 1-2-gram scale synthesis;

INDUSTRIAL APPLICATIONS

Na-ion anode in replacement of hard carbon

For further information, please contact us (Ref 06038-01)