Bhadra Abhirup, Swathilakshmi S, Mittal Uttam, Sharma Neeraj, Sai Gautam Gopalakrishnan, Kundu Dipan
School of Chemical Engineering, UNSW Sydney, Kensington, NSW, 2052, Australia.
Department of Materials Engineering, Indian Institute of Science, Bengaluru, 560012, India.
Small Methods. 2024 Dec;8(12):e2400070. doi: 10.1002/smtd.202400070. Epub 2024 Apr 19.
H co-intercalation chemistry of the cathode is perceived to have damaging consequences on the low-rate and long-term cycling of aqueous zinc batteries, which is a critical hindrance to their promise for stationary storage applications. Herein, the thermodynamically competitive H storage chemistry of an attractive high-voltage cathode LiMnO is revealed by employing operando and ex-situ analytical techniques together with density functional theory-based calculations. The H electrochemistry leads to the previously unforeseen voltage decay with cycling, impacting the available energy density, particularly at lower currents. Based on an in-depth investigation of the effect of the Li to Zn ratio in the electrolyte on the charge storage mechanism, a purely aqueous and low-salt concentration electrolyte with a tuned Li/Zn ratio is introduced to subdue the H-mediated charge storage kinetically, resulting in a stable voltage output and improved cycling stability at both low and high cathode loadings. Synchrotron X-ray diffraction analysis reveals that repeated H intercalation triggers an irreversible phase transformation leading to voltage decay, which is averted by shutting down H storage. These findings unveiling the origin and impact of the deleterious H-storage, coupled with the practical strategy for its inhibition, will inspire further work toward this under-explored realm of aqueous battery chemistry.
人们认为，阴极的氢共嵌入化学对水系锌电池的低倍率和长期循环具有破坏性影响，这严重阻碍了其在固定储能应用中的前景。在此，通过采用原位和非原位分析技术以及基于密度泛函理论的计算，揭示了具有吸引力的高压阴极LiMnO的热力学竞争氢存储化学。氢电化学导致了此前未曾预料到的循环电压衰减，影响了可用能量密度，尤其是在较低电流下。基于对电解液中锂锌比对电荷存储机制影响的深入研究，引入了一种锂锌比经过调整的纯水系、低盐浓度电解液，以在动力学上抑制氢介导的电荷存储，从而在低和高阴极负载下都能实现稳定的电压输出并提高循环稳定性。同步加速器X射线衍射分析表明，反复的氢嵌入会引发不可逆的相变，导致电压衰减，而通过阻止氢存储可以避免这种情况。这些揭示有害氢存储的起源和影响以及抑制它的实用策略的发现，将激发在这个尚未充分探索的水系电池化学领域的进一步研究工作。
