# Improved dehydrogenation performance of LiAlH4 doped with BaMnO3

## TL;DR

Adding BaMnO3 to LiAlH4 improves its hydrogen release performance by lowering the required temperature and speeding up the process.

## Contribution

BaMnO3 doping significantly reduces the activation energy and enhances the hydrogen desorption properties of LiAlH4.

## Key findings

- The starting hydrogen release temperature of LiAlH4 was reduced to 109−115 °C with BaMnO3 doping.
- The activation energy for hydrogen desorption decreased by 30–34 kJ/mol in the doped samples.
- MnO2 and Ba-containing species synergistically enhance the dehydrogenation performance of LiAlH4.

## Abstract

Due to its high gravimetric capacity of hydrogen (10.5 wt%), LiAlH4 has been regarded as a promising material for solid-state hydrogen storage material for onboard usage. However, high decomposition temperature, poor kinetics and irreversibility retard its application. To counter this problem, various weight percentages of BaMnO3 are introduced into the LiAlH4 system as an additive in this work. As a result, the starting hydrogen release of LiAlH4 was reduced to 109−115 °C and the second desorption temperature occurred at around 134−158 °C, much lower than pure LiAlH4. The isothermal desorption kinetics also proved that faster desorption kinetics can be observed at 90 °C for 80 min. About 2.00−2.60 wt% of H2 could be desorbed by the composite, whereas only <1.00 wt% of H2 was desorbed by undoped LiAlH4. Additionally, adding BaMnO3 reduced the activation energies by 30 kJ/mol for the first stages and 34 kJ/mol for the second stages. Based on the X-ray diffraction result, the active species formed of MnO2 and Ba or Ba−containing materials are believed to be responsible for the noticeable enhancement in the desorption properties of LiAlH4.

•H2 storage properties of BaMnO3-doped LiAlH4 are investigated.•Doped with BaMnO3 improved the H2 desorption properties of LiAlH4.•The activation energy for two stages of the doped sample is decrease.•MnO2 and Ba-containing species display a synergistic effect on the dehydrogenation of LiAlH4.

H2 storage properties of BaMnO3-doped LiAlH4 are investigated.

Doped with BaMnO3 improved the H2 desorption properties of LiAlH4.

The activation energy for two stages of the doped sample is decrease.

MnO2 and Ba-containing species display a synergistic effect on the dehydrogenation of LiAlH4.