Enabling high areal capacity for Co-free high voltage spinel materials in next-generation Li-ion batteries

Abstract

The rapidly growing technological demand for lithium-ion batteries has prompted the development of novel cathode materials with high energy density, low cost, and improved safety. High voltage spinel, LiNi 0.5 Mn 1.5 O 4 (LNMO), is one of the most promising candidates yet to be commercialized. The two primary obstacles for this material are the inferior electronic conductivity and fast capacity degradation in full cells due to the high operating voltage. By systematically addressing these limitations, we successfully develop a thick LNMO electrode with areal capacity loadings up to 3 mAh⋅cm À 2. The optimized thick electrode is paired with a commercial graphite anode at both the coin cell and pouch cell level, achieving a full cell capacity retention as high as 72% and 78%, respectively, after 300 cycles. We attribute this superior cycling stability to careful optimizations of cell components and testing conditions, with a specific focus improving electronic conductivity and high voltage compatibility. These results suggest precise control of materials quality, electrode architecture and electrolyte optimization can soon support the development of a cobalt-free battery system based on a thick LNMO cathode (>4 mAh⋅cm 2), which will eventually meet the needs of next-generation Li-ion batteries with reduced cost, improved safety, and assured sustainability.

Unveiling the Stabilities of Nickel‐Based Layered Oxide Cathodes at an Identical Degree of Delithiation in Lithium‐Based Batteries

“…Therefore, it is necessary to evaluate whether the electrolyte used here is stable enough to undertake the high voltage of 4.65 V required by NMC811. As demonstrated in Note S1 (Supporting Information) and previous studies, [ 35,36 ] the used electrolyte in this study is stable up to 4.85 V. The images of the dissembled cells in Figure S4 (Supporting Information) show that there is still a noticeable amount of electrolyte left in the cells after cycling. Additionally, the reassembled cell with the cycled NMC811 and a new lithium‐metal anode (Figure S5, Supporting Information) still experiences a rapid increase in the cut‐off charge voltage.…”

“…As to the reasons for the aggravated electrode/electrolyte interactions and thicker CEI in NMC811, it is proposed to primarily result from the compositional difference between NMC811 and LNO. Specifically, although NMC811 requires a higher voltage to reach the given degree of delithiation, the electrochemical performance in Note S1 (Supporting Information), along with previous studies, [ 35,36 ] demonstrates that the used electrolyte is stable for this study. Meanwhile, recent studies have indicated that electrolyte oxidation decomposition on higher‐ and lower‐Ni NMC cathodes is not driven by cell voltage.…”

From Fundamental Understanding to Engineering Design of High‐Performance Thick Electrodes for Scalable Energy‐Storage Systems

“…Because increasing research attention has been paid to thick electrode design, an overview of the research statistics in this field is essential to benchmark the current research status. Here, we summarize the information on the abovementioned electrode design parameters as well as energy/power density indicators from 62 publications related to thick electrodes, [ 8,9,12–15,20,21,24,39,40,43–45,50,62–104 ] (Table S2, Supporting Information) and the results of the statistical analysis are discussed in the following section.…”

Elucidating the Effect of Borate Additive in High‐Voltage Electrolyte for Li‐Rich Layered Oxide Materials

“…[19,20] Besides the modification on active materials, many cell components have also been optimized for high-voltage operation such as the binder and conductive agents. [21] However, the compatibility of the electrolyte with the charged state of LRLO is often neglected in the literature. The activation step ubiquitously seen in anionic redox materials occurs at 4.5 V versus Li + / Li 0 .…”