Ni/Fe mixed oxide and natural clay composite as anode material for Li-ion batteries

AUGUSTO RODRÍGUEZ; , MARIELA ORTIZ; JORGE THOMAS; VISINTIN A.

Mar del Plata

Congreso; 34 th Topical Meeting ISE; 2023

International Society of Electrochemistry - ISE

The fast and continuous development of portable electronic devices, such as laptops and cell phones, keeps increasing the demand for a new generation of high-energy and high-capacity materials for electrodes of lithium-ion batteries. While great efforts have been dedicated towards the development of new cathode materials with high capacity, it is also required to continue, alongside, the development of novel anode materials. Transition metal oxides such as NiO and Fe2O3 represent promising candidates for this purpose due to their high discharge capacities; however, some deficiencies must still be overcome in order to reach their industrial and commercial scale application, such as a high level of volumetric expansion that limits the electrode cyclability. We present the synthesis of a Ni/Fe mixed oxide composite as anode material, obtained through the calcination at 400 °C (4 h) of a mixture containing a Ni/Fe layered double hydroxide (Ni0.75Fe0.25(OH)2(CO3)0.125 hydrotalcite) and a 2% of a natural clay sample collected from La Plata, Argentina. Previously, the double hydroxide was obtained by means of a coprecipitation method [1] in the presence of the natural clay. XRD analysis of the double hydroxide and clay mixture before calcination shows the corresponding peaks of the hydrotalcite layered structure as well as some signals related to kaolinite clay . Cyclic voltammetry of the sintered mixture exhibits a reduction peak located at 0.36, 0.50, 0.75, and 1.50 V in well agreement with those reported for other NiO and Fe2O3 anode materials . Charge-discharge performance for the material before and after calcination (without 2% natural clay) shows high initial discharge capacities (>1000 mAh/g); nonetheless, a rapid capacity fade is observed probably due to the well-known phenomenon of volumetric expansion Cyclability of the Ni/Fe/clay oxide shows a considerable improvement, with an initial discharge capacity of 2900 mAh g-1, reaching stability after 40 cycles on 576 mAh g-1 . The calcination and treatment of the natural clay in basic media could have produced an increase in its porosity, a specific surface acting as a buffer against the volumetric expansion in the Ni/Fe mixed oxide.