Ni-rich　layered　lithium　transition　metal　oxides　are　promising　cathode　materials　for　the　next　generation　high　energy　density　lithium　ion　batteries.　However,　high　Ni　content　leads　to　severe　side　reactions　at　cathode/electrolyte　interface,　coupled　with　mechanical　disintegration　significantly　degrading　the　electrochemical　performance　and　safety.　Surface　coating　and　grain　boundary　(GB)　engineering　can　respectively　protect　surface　layer　and　suppress　cracking　issue,　but　direct　comparisons　of　the　individual　effect　of　the　two　methods　at　different　cycling　conditions　has　not　been　fully　explored.　Moreover,　the　two　methods　have　never　been　coupled　together　previously,　let　alone　their　coupling　effect.　Herein,　we　take　LiNi0.8Mn0.1Co0.1O2　as　a　model　material　and　utilize　atomic　layer　deposition　coating　and　annealing　protocol　to　demonstrate　the　individual　and　coupling　effects　of　surface　coating　and　GB　engineering　on　cycling　stability.　GB　engineering　is　found　to　be　more　effective　than　surface　coating　in　enhancing　cycling　stability　due　to　suppressed　intergranular　cracks.　Promisingly,　coupling　GB　engineering　and　surface　coating,　we　can　achieve　superior　cycle　stability　even　upon　high　voltage　cycling　(91%　retention　after　200　cycles　at　2.7-4.7　V),　which　demonstrates　the　importance　to　simultaneously　alleviate　surface　degradation　and　bulk　disintegration　in　design　of　advanced　cathode　materials.