Lithium ion battery demands and a discussion of lithium supply crisis: How worried should we be? Dr. Raj Shah and Ms. Shana Braff Koehler Instrument Company Holtsville, NY, USA Lithium is an essential ingredient in three-quarters of grease production worldwide. During the last decade, the grease industry warily took note of surging demands for lithium for batteries used in plug-in electric vehicles (EVs) and other popular applications. This paper reviews global trends affecting demands and supplies of this unique metal.
Figure 1: Lithium grease (Source: globalsources.com) Lithium Greases According to the 2018 survey of worldwide grease production prepared by NLGI (National Lubricating Grease Institute), 74.18% by volume contains lithium soap thickener. Conventional lithium greases make up 54.51%, and lithium complex greases make up 19.67% of the market share. This was a small decrease from the lithium grease market share of 76.70% reported in the 2017 NLGI survey. Greases thickened with lithium soap were patented in the early 1940s and used initially for aircraft lubrication, according to NLGI’s Lubricating Grease Guide. Most lithium soap greases currently are prepared by reacting lithium hydroxide with 12-hydroxystearic acid in oil to make lithium 12-hydroxystearic acid thickener. Complex lithium greases are prepared by including a short chain dicarboxylic acid, boric acid or other complexing agent in the reaction to form thickener. David Turner noted that conventional or simple lithium greases are popular multi-purpose products because they are economical and have desirable resistance to heat and water, good shear stability and easy pumpability. Complex lithium greases have higher dropping points (~500 F or 260 C) than simple lithium greases (~385 F or 195 C) as well as even better mechanical stability and water resistance. Mike Johnson discussed the various grease thickener chemistries that are available. Barium and calcium soap greases typically have better water-resistance properties compared to lithium greases but have other disadvantages related to oxidation stability and pumpability. Sodium greases are usually more cost-efficient than lithium greases, but their water-resistance is significantly weaker. Aluminum complex multi-purpose greases are water-resistant but saddled with modest oxidation resistance, and they are relatively expensive. Polyurea-thickened greases are ashless and have outstanding oxidation resistance and low noise emissions, but their corrosion resistance and work stability are limited. - 26 VOLUME 82, NUMBER 5
