Reactive boride infusion stabilizes Ni-rich cathodes for lithium-ion batteries

Abstract

Engineered polycrystalline electrodes are critical to the cycling stability and safety of lithium-ion batteries, yet it is challenging to construct high-quality coatings at both the primary-and secondaryparticle levels. Here, we present a room-temperature synthesis route to achieve full surface coverage of secondary particles and facile infusion into grain boundaries, thus offering a complete "coatingplus-infusion" strategy. Cobalt boride metallic glass is successfully applied to Ni-rich layered cathode LiNi 0.8 Co 0.1 Mn 0.1 O 2 . It dramatically improves the rate capability and cycling stability, including under high-discharge-rate and elevated-temperature conditions and in pouch full cells.The superior performance originates from simultaneous suppression of microstructural degradation of intergranular cracking and side reactions with electrolyte. Atomistic simulations identified the critical role of strong selective interfacial bonding, which offers not only a large chemical driving force to ensure uniform reactive wetting and facile infusion but also lowered the surface/interface 2 oxygen activity, contributing to the exceptional mechanical and electrochemical stabilities of the infused electrode.

Determining the Criticality of Li‐Excess for Disordered‐Rocksalt Li‐Ion Battery Cathodes

“…Moreover, in practice, large particles are desirable for improved cathode packing density, reduced side reactions with the electrolyte, less TM-dissolution (e.g., Mn-dissolution from Mn-DRX), and surface treatments for enhanced cycling stability. [58,59] To cycle large particles, intrinsic Li-diffusivity must be sufficiently high to support long-range Li-diffusion at a reasonable rate. Therefore, we believe that 0-TM percolation enabled by Li-excess will continue to play an important role in the design of the DRX cathodes, and detailed studies on the SRO effect on the percolation or the role of the thermodynamic factor on the chemical Li diffusivity must be conducted to optimize the 0-TM percolation for the fastest Li-transport.…”

Revealing Roles of Co and Ni in Mn‐Rich Layered Cathodes

“…[ 1,2 ] Therefore, developing the cathodes possessing both the high performance and low cost has been one of the frontiers in the LIB field. Although the Co‐containing cathodes like LiCoO 2 (LCO), [ 3,4 ] ternary Li(Ni x Mn y Co z )O 2 (NMC; x + y + z = 1; x > 1/3), [ 5,6 ] and Li(Ni 0.80 Co 0.15 Al 0.05 )O 2 (NCA) [ 7,8 ] are now widely used in the current commercial batteries, the call for low‐Co and Co‐free cathodes is an unstoppable trend due to the high cost, high toxicity, and child labor abuse in mining of Co. [ 9–13,15 ] In contrast, the price of Ni is only one‐third of Co, whereas Mn is even cheaper at a fifth of the price of Ni, while the global Mn reserves are even two orders of magnitude higher than those of Ni and Co (Figure S1, Supporting Information). [ 2,14–16 ] Furthermore, the biological toxicity of Mn is also much less than that of Co and Ni.…”

Functional additives for solid polymer electrolytes in flexible and high‐energy‐density solid‐state lithium‐ion batteries

“…However, high-voltage stability and high-rate cycling often trigger accelerated degradation, premature failure, and safety issues. 147 Considering the internal drawbacks of liquid electrolytes for high-voltage cathodes, including safety hazards, 148 parasitic side reactions, 149 lithium dendrite growth, 150 metal ion dissolution, 151 and so on, SPEs show obvious advantages in addressing these issues in high-voltage cathodes. However, the commonly used PEO-based polymer electrolytes have limited oxidative stability in state-of-the-art high-voltage cathodes, limiting their utility.…”