This guide outlines key points for preparing primary research manuscripts for submission to Nature Communications. The corresponding author should be familiar with the Nature journals’ editorial policies and is solely responsible for communicating with the journal and managing communication between coauthors. Before submission, the corresponding author ensures that all authors are included in the author list and agree with its order, and that they are aware the manuscript is to be submitted. For more information on editorial and authorship policies please review our Guide to Authors.Cover letterAlthough optional, the cover letter is an excellent opportunity to briefly discuss the context and importance of the submitted work and why it is appropriate for the journal. Please avoid repeating information that is already present in the abstract and introduction. The cover letter is not shared with the referees, and should be used to provide confidential information, such as conflicts of interest, and to declare any related work that is in press or submitted elsewhere.Main manuscriptIntroductionThe rapidly boosting market for consumer electronics and electric vehicles (EVs) has motivated the tremendous ongoing efforts in researching lithium ion battery materials and chemistry, aiming to improve energy and power density, enhance safety, prolong lifetime, and reduce cost. An important aspect of the battery research is to identify the fading pathways of battery particles and electrodes at multiple length/time scales in response to the real-world operating conditions\cite{Bak_2018} . The hierarchical architecture of the lithium-ion batteries\cite{Varzi_2017} is vital to the desired functionality of on-demand energy storage and release. Independent efforts have been devoted to the study of different battery components (e.g., cathode, anode, electrolyte, binder, etc.). In practice, however, it is the synergy among all of the battery components that determines the ultimate battery performance. In lithium ion batteries, the cathode materials still present a bottleneck for further improving the energy density of lithium ion batteries\cite{Nitta_2015} . It is, therefore, of fundamental interest and importance to systematically investigate the cathode materials’ morphological, chemical, and mechanical properties, which intertwine at different time and length scales [ref]. Nickel-rich layered materials LiNi1-x-yMnxCoyO2 (NMC) are promising cathode candidate for high energy density lithium ion batteries\cite{Liu_2015},\cite{Lu_2013},\cite{Kim_2006}. They, however, suffer from the capacity fade, especially, when charged to a high cut-off voltage, which is a necessary procedure to unleash the high energy density potential of this material\cite{Ryu_2018} . In the current landscape of the NMC research, we are seeing a growing emphasis on the compounds with even higher Ni and lower Co/Mn content. Such a trend further accentuates the need to understand and, subsequently, to enhance the structural and chemical stability of the nickel-rich NMC cathode. This is because, while the increment in Ni content offers more redox active cations for the charge compensation during energy storage/release and, thus, favors high energy density, the reduction in Co and Mn content could harm the morphological integrity\cite{Kim_2006}, thermal robustness\cite{Guilmard_2003}, and lattice structural stability\cite{Saadoune_1996},\cite{ZHECHEVA_1993}.The electro-chemo-mechanical interplay in nickel-rich NMC cathode is an active research topic that has attracted a great amount of attention \cite{Xu_2018}. The development of morphological defects, i.e. micro-cracks, is not only dependent on the global cathode composition\cite{Ryu_2018}, but also can be largely influenced by the difference in the externally applied reaction driving forces including the cycling rate\cite{Xia_2018},\cite{Xu_2017}, the cycling voltage window\cite{Yan_2017}[Yuwei Joule; ], and the environmental temperature\cite{Mu_2018},\cite{Mu_2018a},\cite{Yan_2018},\cite{Wei_2018},\cite{Finegan_2015}. Advanced imaging methods, e.g. synchrotron-based x-ray probes\cite{Lin_2017},\cite{Wang_2016},\cite{Zhang_2016},\cite{Ebner_2013},\cite{M_ller_2018},\cite{Tsai_2018},\cite{Wei_2018a}, scanning/transmission electron microscopy\cite{Besnard_2017},\cite{Wang_2017},\cite{Kuppan_2017}, and atomic force microscopy\cite{Becker_2013} have been employed for in-depth investigations in this field. Among all these diagnostic tools, the x-ray probes with sufficient spatial resolution and compositional/chemical sensitivity show advantages for correlating the morphological and chemical features of the material. Particularly, when coupled with advanced computing methods for quantification\cite{Liu_2016},\cite{Duan_2016},\cite{Zhang_2017} and modeling\cite{Kan_2018},\cite{M_ller_2018} of the data, the x-ray imaging methods have been demonstrated to be non-invasive, effective and informative.  Nevertheless, there has not been a study for the electrode-level to offer insights into many-particle electro-chemo-mechanical analysis with nanometer spatial resolution that could resolve the structural and chemical details within every individual particle. Such a study would open an avenue for probing the spatially resolved charge distribution and chemomechanical response for an entire battery composite electrode.In this work, we combined hard x-ray phase contrast nano-tomography, transmission x-ray microscopy, nanoscale hard x-ray spectro-microscopy, soft x-ray absorption spectroscopy and transmission electron microscopy to systematically investigate the morphological and chemical degradation in LiNi0.6Mn0.2Co0.2O2 (NMC622) electrode under fast charging conditions (5C). At the atomic scale, we observed the local phase transition, which is associated with and is likely responsible for the initiation of the micro-cracks. Such a process propagates to the secondary particle level (i.e. at the mesoscale), where we elucidated two stages of the particle cracking, which entail different chemical responses on the crack surface: 1) the host material’s local lattice structural transition and 2) liquid electrolyte infiltration that forms new diffusion pathway for lithium ions. We further quantified the x-ray phase contrast nano-tomography data of the whole cathode electrode and reported the depth-dependent particle fracturing profile at the electrode level, which has depth-dependent chemical consequences as confirmed by the soft x-ray absorption spectroscopic measurements. The lateral heterogeneity in the electrode-level cracking profile suggests that the degree of local electrode usage evolves as a function of location and time. The heterogeneity in the degree of particle cracking across the electrode is attributed to the local morphological damage and the mismatch between local electric and ionic conductivity. Finite element modeling (FEM) is used to gain further insights into the electrode level strain distribution and propagation. Our results offer valuable insights that could inform the rational design of next-generation battery material with superior electro-chemo-mechanical robustness.