Molecular-level interphase design for sustainable batteries
type: CreativeWork
description: Since the first commercialization of Li-ion batteries (LIBs) in 1991, they have continued to power the society for decades. However, the ever-growing demands pose challenges to their sustainability in terms of restricted energy density, inadequate cycle life, and limited key resources. In the first part of this thesis (chapter 2), efforts made within Li batteries, with respect to sustainability in energy density, cycle life and resources are reported in three sub-chapters discussed below. Use of pure metallic Li is an important strategy for full utilization of the inherently high energy density of Li. In chapter 2.1, novel research is devoted towards quantifying major Li loss pathways for the first time. Based on the fundamental understanding gained from the quantified correlation between major Li loss forms, a rational interphase design principle for achieving highly reversible lean Li and lean electrolyte Li metal batteries (LMBs) from a holistic perspective is proposed. An inorganic-rich insoluble inner solid-electrolyte interphase (SEI) layer with high electron passivity is established, as well as the suppression of organic SEI dissolution. This work has demonstrated an ultra-low Li loss rate (mainly from Li corrosion and SEI dissolution) of 0.13 μAh cm-2 h-1 and an ultra-low SEI growth rate (mainly from Li corrosion) of 3.20 mΩ cm-2 h-1, leading to over 5000 h Li metal cycling stability at a Li utilization rate of 50%, which is very high in lean Li||Li symmetric cells. Based upon this novel molecular-level interphase design, full LIB cells have been fabricated and validated with promising results. A Li||LiFePO4 (LFP) full cell with lean Li (negative to positive, i.e., N/P ratio of 2) subject to a deep cycling rate of 0.2 C over 700 cycles running over 280 days demonstrates 90% capacity retention at an average Coulombic efficiency (CE) of 99.99%, and impressively a 480 Wh kg-1 Ah-level Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch cell with a lean N/P ratio of 1.02 and…
abstract: Since the first commercialization of Li-ion batteries (LIBs) in 1991, they have continued to power the society for decades. However, the ever-growing demands pose challenges to their sustainability in terms of restricted energy density, inadequate cycle life, and limited key resources. In the first part of this thesis (chapter 2), efforts made within Li batteries, with respect to sustainability in energy density, cycle life and resources are reported in three sub-chapters discussed below. Use of pure metallic Li is an important strategy for full utilization of the inherently high energy density of Li. In chapter 2.1, novel research is devoted towards quantifying major Li loss pathways for the first time. Based on the fundamental understanding gained from the quantified correlation between major Li loss forms, a rational interphase design principle for achieving highly reversible lean Li and lean electrolyte Li metal batteries (LMBs) from a holistic perspective is proposed. An inorganic-rich insoluble inner solid-electrolyte interphase (SEI) layer with high electron passivity is established, as well as the suppression of organic SEI dissolution. This work has demonstrated an ultra-low Li loss rate (mainly from Li corrosion and SEI dissolution) of 0.13 μAh cm-2 h-1 and an ultra-low SEI growth rate (mainly from Li corrosion) of 3.20 mΩ cm-2 h-1, leading to over 5000 h Li metal cycling stability at a Li utilization rate of 50%, which is very high in lean Li||Li symmetric cells. Based upon this novel molecular-level interphase design, full LIB cells have been fabricated and validated with promising results. A Li||LiFePO4 (LFP) full cell with lean Li (negative to positive, i.e., N/P ratio of 2) subject to a deep cycling rate of 0.2 C over 700 cycles running over 280 days demonstrates 90% capacity retention at an average Coulombic efficiency (CE) of 99.99%, and impressively a 480 Wh kg-1 Ah-level Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) pouch cell with a lean N/P ratio of 1.02 and…
author: Fei, Minfei
language: eng
keywords: Battery, Energy density, Interphase, Sustainability, Resource
license: https://www.repository.cam.ac.uk/bitstreams/22167d87-d7b2-4282-8446-a0e953670fcb/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2024-06-01
date modified: 2026-07-22T22:24:27Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.112511