The Formation/Decomposition Equilibrium of LiH and its Contribution on Anode Failure in Practical Lithium Metal Batteries

Abstract

Discovering the underlying reason for Li anode failure is ac ritical step towards applications of lithium metal batteries (LMBs). In this work, we conduct deuterium-oxide (D 2 O) titration experiments in an ovel on-line gas analysis mass spectrometry (MS) system, to determine the content of metallic Li and lithium hydride (LiH) in cycled Li anodes disassembled from practical LiCoO 2 /Li LMBs.T he practical cell is comprised of ultrathin Li anode (50 mm), high loading LiCoO 2 (17 mg cm À2 ,2 .805 mAh cm À2)a nd different formulated electrolytes.O ur results suggest that the amount of LiH accumulation is negatively correlated with cyclability of practical LMBs.M ore importantly,w er eveal at emperature sensitive equilibrium (Li + 1/2 H 2 Ð LiH) governing formation and decomposition process of LiH at Li anode.Webelieve that the unusual understanding provided by this study will draw forth more insightful efforts to realizee fficient Li protection and the ultimate applications of "holy grail" LMBs.

Confronting the Challenges in Lithium Anodes for Lithium Metal Batteries

“…Furthermore, there are some new issues with practical lithium metal batteries. For instance, LiH observed in practical batteries leads to the pulverization of anode; [17] the corrosion of lithium anodes during calendar ageing is observed for the first time by cryo-electron microscopy; [171] the external pressure management of the pouch battery has an effect on the improvement of battery's performance. [16] These problems urgently need to arouse researchers' extensive attention.…”

“…Xu et al. [ 17 ] studied practical battery with an ultra‐thin lithium anode and a high‐load cathode (LiCoO 2 ). It was found that in anodic surface, the proportion of LiH in the anodic byproducts increases dramatically (from 0.74% to 16.55%) after 20 cycles.…”

“…Factors such as small battery pressure and the accumulation of LiH have also been demonstrated as the cause of lithium anode's failure under practical conditions (low N/P ratio, lean electrolyte and pouch battery system). [ 16 , 17 ] Additives, artificial solid electrolyte interphase (SEI), solid electrolyte, and 3D anode hosts, etc., are proposed to solve the lithium anode problems. Among them, the dual‐salt and tri‐salt electrolyte systems play synergistic effect in building stable SEI.…”

Uncovering LiH Triggered Thermal Runaway Mechanism of a High‐Energy LiNi0.5Co0.2Mn0.3O2/Graphite Pouch Cell

“…[13,23] Very recently, our group found the existence of LiH on lithium metal anode surface, and pointed out its influence on anode failure in practical lithium metal batteries. [24] Herein, by employing a delicately-designed deuterium-oxide (D 2 O) titration device connecting with an on-line gas analysis mass spectrometry (MS) system (Figure 4a), we unprecedentedly identify the existence of LiH on the surface of the graphite anode. Fully-lithiated graphite (100% SOC) and fully-delithiated graphite (0% SOC) are titrated by deuterium-oxide (D 2 O) with the following guideline reactions:…”

FEC Additive for Improved SEI Film and Electrochemical Performance of the Lithium Primary Battery

“…Consequently, by combining a lithium anode with other advanced cathode materials, a specific energy of more than 400 Wh kg −1 can be easily obtained. Compared to rechargeable lithium batteries, lithium primary batteries play an important role in the electronic industry, automation devices, aerospace and military equipment under some special conditions, due to the portability, wide operating temperature, stable discharge performance and long storage life [4][5][6][7]; however, the chemical nature of lithium metal is very active, where it will react quickly and release hydrogen when it encounters water, causing great safety hazards. As such, non-aqueous electrolytes, including lithium inorganic compounds as lithium salts and organic substances as solvents, are usually used in lithium primary batteries.…”