Developing versatile, reliable, and high-performance materials and electrochemical energy storage devices, such as next generation batteries, that meet the diverse needs in commercially-relevant scenarios presents multiple, difficult technical challenges. Yet it is known that scalable approaches that overcome these challenges represent an integral element in addressing what is arguably the grand challenge of our time —powering human society using carbon-neutral energy sources. Realistic solutions must therefore consider not only the performance of the materials that constitute an individual electrochemical cell, but must also consider how such cells perform when integrated into a battery system, as well as the overall sustainability of critical materials used in fabricating cells at the scale needed. The significance of overall sustainability as a constraint for how, where, and at what scale energy is stored is manifold. It, on the one hand, means that at the cell level, it is advantageous to design batteries that exhibit excellent durability over extended charge/discharge cycling, as well as during storage. An extended cell lifetime is desirable because it would simultaneously reduce the amortized cost of the energy storage system and minimize the impact of the battery manufacturing and disposal processes on the environment. It is understood, however, that the materials required to achieve long-duration storage are not necessarily the most sustainably sourced. Indeed, sustainability of next-generation batteries, is currently thought to hinge on the use of inexpensive, earth-abundant, diversely sourced raw materials. Consequences for battery production when one or more of these conditions are not met are vividly illustrated by the recent impacts soaring prices of critical materials (e.g., Li and Co) in international markets have had on battery production costs and market uptake in electric vehicles. Such consequences are also evident in the rising demand for alternative electrode materials that are intrinsically earth-abundant and cost-effective (e.g., Fe, Zn, Mn, and Si). However, these “next-generation” battery chemistries are in general at a much earlier state of development than state-of-art Li-ion technology and serious challenges associated with irreversibility of the electrode processes must be overcome to mitigate fast capacity fading, and limited battery service life.Research in this thesis takes these challenges as a foundation for in-depth studies of the role the multi-scale architecture of a battery electrode plays in long-term viability of electrochemical cells. In Chapter 1, I first review known, fundamental limitations of batteries based on earth-abundant materials chemistries. The overall perspective on the inherent difficulty of creating batteries from earth-abundant materials presented in that chapter is informed by the fact that many of the limitations are actually well-known and well-studied. Indeed, were it not for the fundamental nature of them, batteries based on these chemistries would otherwise have long been adopted for commercial applications. Motivated by these considerations, Chapter 1 also reviews a large, and growing literature addressing the failure mechanisms of representative next-generation electrode materials using complementary characterization methods including atomic-resolution transmission electron microscopy and synchrotron diffraction. On this basis, I discuss and evaluate potential strategies for mitigating these—either extrinsic or intrinsic—instabilities. It is found that irreversibility primarily occurs by means of physical orphaning and chemical degradation. The former describes the propensity of an electrode material to fail when the electrochemically active component in an electrode mechanically breaks away from the current source —oftentimes due to repeated, large volume change over cycling. This mode of failure cuts off electrical transport to/from the active material and therefore electrochemically deactivates the battery electrode. Conventional wisdom states that a highly-electrically-conductive non-planar architecture in which the electronic conductance (σe) far exceeds the ionic conductance (σion), (i.e., σe>>σion) can suppress this tendency. Results reported in the thesis, surprisingly, reveal that the opposite holds true: non-planar electrode architectures with very high σe values biases deposition to the topmost surface of the non-planar electrode, promoting outward growth of metal deposits analogous to what might be expected for a conventional planar (2-dimensional) electrode architecture. Analysis of the coupled transport of charged species (electrons and ions) in the electrode in fact suggests that a moderate electrical conductivity (σe~σion) is preferred. Under such conditions, ions are firstly transported further into the electrode architecture before they are reduced, which makes better use of the full hosting volume of the non-planar framework. Leveraging this new design rule, I show that unprecedented, close-to-unity reversibility (quantified in terms of the Coulombic Efficiency, CE) is achieved at high areal capacities. (Chapter 2) Chemical degradation, in contrast, originates from the unfavorable, parasitic reactions occurring in the electrodes. Such parasitic reactions negatively impact the cycling performance through active material loss to the electrolyte by dissolution or electrochemical loss due to surface passivation and hence high overpotentials. Solvolytic hydrolysis of the electrolyte is particularly revealed as a root cause for chemical degradation. For example, the hydrofluoric acid molecules generated by F-containing salts can result in detrimental leaching of transition metals in a group of promising cathode materials that replace Co—a progressively expensive and depleted element—by Mn. In turn, by task-specific engineering of the electrolyte that stabilizes both the anode and the cathode, we demonstrate Li

LiMn2O4 batteries with stable charge-discharge performance over 1000 cycles (Chapter 3). We further explore cyclized-polyacrylonitrile (c-PAN) as a versatile material platform with good electrical conductivity and chemical polarity for tackling both the physical orphaning and the chemical dissolution problems at the same time. Results obtained show the potential of c-PAN as a multi-functional binder for sustainable electrodes such as Si and MnO2. Taken together, the studies underscore the coupled nature of electrochemical processes of battery interest. As will be pointed out in Chapter 4, engineering strategies that simultaneously guarantee robust transport paths and chemical stability are requisite to the electrochemical stability required in deployable applications.