In this study, we first examined the hydrogen release, uptake, and reversibility properties of the KLi3(NH2)(4)-4LiH system and elucidated the influence of potassium cations' substitution into LiNH2 on the hydrogen storage properties of the LiNH2-LiH composite. Our results show that mixing of the potassium cations into LiNH2 can destabilize LiNH2, therefore decreasing the hydrogen desorption temperature and enhancing hydrogen desorption rate of the LiNH2-LiH system. Notably, the KLi3(NH2)(4)-4LiH composite exhibits a superior cycling stability compared with the LiNH2-LiH composite prepared under the same condition. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.