In situ fracture behavior of single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811)

Single crystal particle morphologies have become highly desirable for next generation cathode materials, removing grain boundary fracture and thereby reducing the surface area exposed to electrolyte. The intrinsic mechanical behavior of single crystal layered oxides, however, is poorly understood. Here, faceted single crystal LiNi0.8Mn0.1Co0.1O2 (NMC811) particles are compressed in situ in a scanning electron microscope (SEM), to determine mechanical deformation mechanisms as a function of crystallographic orientation. In situ, the dynamical deformation sequence observed is initial cracking at the compression zone, followed by accelerated transparticle crack propagation and concurrent (0001) slip band formation. The greatest loads and contact pressure at fracture, non-basal cracking, and activation of multiple basal slip systems in larger (>3 μm) particles, occur for compression normal to the (0001) layered structure. Loading on {012} preferentially activates basal fracture and slip at lower loads. Regardless of particle orientation, non-basal slip systems are not observed, and non-basal cracking and particle rotation occur during compression to compensate for this inability to activate dislocations in 3-dimensions. Crystallographic dependent mechanical behaviour of single crystal NMC811 means that particle texture in cathodes should be monitored, and sources of localised surface stress in cathodes, e. g. particle-to-particle asperity contacts during electrode manufacture, should be minimised

Fracture testing of lithium‐ion battery cathode secondary particles in‐situ inside the scanning electron microscope

Fracture of cathode secondary particles is a critical degradation mechanism in lithium-ion batteries. The microindentation strength of LiNi0.8Mn0.1Co0.1O2 secondary particles is measured in situ in the scanning electron microscope (SEM), enabling dynamical imaging of fracture. Crack propagation is intergranular between primary particles when induced by compressing between flat platens (analogous to calendaring), and with a cono-spherical indenter (representing particle-particle contact). Fracture occurs directly beneath the cono-spherical tip and at the centre of secondary particles when compressed between flat platens. Finite element modelling of stress states provides insight into the dependence of fracture load upon cohesive strength and particle toughness. Secondary particle indentation strength decreases with increasing secondary particle size, with cycling, and with increasing state of charge. The indentation strength decrease is greatest in earlier stages of delithiation. The novel microindentation technique allows assessment of strength and toughness of different cathode morphologies, aiding prediction of optimal particle structure and processing conditions

Primary accumulation in the Soviet transition

The Soviet background to the idea of primary socialist accumulation is presented. The mobilisation of labour power and of products into public sector investment from outside are shown to have been the two original forms of the concept. In Soviet primary accumulation the mobilisation of labour power was apparently more decisive than the mobilisation of products. The primary accumulation process had both intended and unintended results. Intended results included bringing most of the economy into the public sector, and industrialisation of the economy as a whole. Unintended results included substantial economic losses, and the proliferation of coercive institutions damaging to attainment of the ultimate goal - the building of a communist society

Grain production and utilization in Russia and the USSR before collectivisation

This thesis is concerned with analysing the available data on grain production and its utilisation from the time when the earliest grain statistics became available in pre-revolutionary Russia until the eve of mass transformation of Soviet agriculture that was associated with mass collectivisation in 1929. The pre-revolutionary period and post revolutionary period are treated separately in two separate parts of the thesis. In each part I describe the methods of collecting and organising statistics related to the production and utilisation of grain. I discuss the circumstances in which these statistics were gathered and I attempt to assess the reliability of these data and place them in a more meaningful and more comparative form. I then present an account of the available works that have attempted to analyse the balance of grain production and its utilisation. I conclude by making my own assessment of the balance and compare it with the general conceptions held on the nature of the grain problem. I conclude that the balance of grain production and utilisation was a highly complex phenomenon dependent upon the inter-relationship of demographic, economic and agronomic factors that differed from region to region and from time to time. The full complexity of these inter-relationships was little understood by the political leadership of the time

Mapping and evaluating the major famines of modern times

This abstract reports on an international project being carried out at Nazarbayev University that provides a more detailed picture of the geography and chronology of the largest famines of the twentieth century. Our preliminary results on the Soviet famine of 1932-33 challenge many of the conventional views. Because of international interest in this work, preliminary results concerning mapping the Soviet famine have been published in Russia and Ukraine, and are available on the website of the Russian State Archive Administration

Soviet economic balances and trends, 1926-1941

SIGLELD:8318.1708(SSRC-B--00/23/0004) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Inter-sectoral transfers and sources of capital investment in the USSR

SIGLEAvailable from British Library Document Supply Centre- DSC:8318.17080F(ESRC/BOO--23/0061)fiche / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Economic Development of Eurasian Countries from Wider Perspectives: Proceedings of the International Workshop

Yasushi NAKAMURA (ed.)1. The Deficiency of Competitiveness: Did Socialism Fail to Foster It? / Choi, Syngjoo(SNU) ; Kim, Byung-Yeon(SNU) ; Lee, Jungmin(SNU & IZA) ; Lee, Sokbae(Columbia University)2. Gender Inequality and Sex Ratios in China, India and Russia / Bhattacharya, Prabir C.3. A Cooperative Strategy: The Economic Roles of China, Russia and Japan under the OBOR Initiative / Hsieh, Wen-jen4. Soviet peasant budget studies and demographic data in the long run and through periods of crisis. / Wheatcroft, S.G.(University of Melbourne, & SRC Hokkaido University)5. Program of the Workshop100, [2] p

Mechanical properties of cathode materials for lithium-ion batteries

Mechanochemical degradation processes such as the fracture of cathode particles play a major role in limiting the service life of advanced lithium-ion batteries (LIBs). In order to help alleviate the degradation of battery performance, it is necessary to measure the relationship between the degradation of the mechanical properties of cathodes and their concomitant degradation of electrochemical performance. In this review, measurements of the mechanical properties of LIB cathode materials are summarized from the literature, along with the range of experimental methods used in their determination. Dimensional changes that accompany charge and discharge are compared for active materials of olivine, spinel, and layered atomic structures. The sensitivity of indentation hardness, Young's modulus and fracture strength to grain size, porosity, state of charge and charge/discharge history are critically reviewed and discussed with reference to the behavior of conventional, electrically inactive solids. This approach allows for the identification of microstructural properties that dictate the mechanical properties of LIB cathode materials